Design criteria for prompt radiation limits on the relativistic heavy ion collider site.

PubMed

Stevens, A; Musolino, S; Harrison, M

1994-03-01

The Relativistic Heavy Ion Collider (RHIC) is a superconducting colliding beam accelerator facility that is currently under construction. Relatively small amounts of energy depositing in the coils of superconducting magnets can result in a "quench," the irreversible transition to the normal resistive state. The quench limit of superconducting magnets, therefore, constrains local beam loss throughout the injection, acceleration, and storage cycles to extremely low levels. From a practical standpoint, it follows that there is essentially no prompt radiation in most regions due to normal operations. The design of shielding is, therefore, principally driven by the consequences of a single pulse fault at full energy in one of the two storage rings. Since there are no regulatory requirements or guidance documents that prescribe radiological performance goals for this situation, the RHIC Project has proposed a scheme to classify the various areas of the RHIC complex based on Design Basis Accident faults. The criteria is then compared to existing regulatory requirements and guidance recommendations.

Impact parameter sensitive study of inner-shell atomic processes in the experimental storage ring

NASA Astrophysics Data System (ADS)

Gumberidze, A.; Kozhuharov, C.; Zhang, R. T.; Trotsenko, S.; Kozhedub, Y. S.; DuBois, R. D.; Beyer, H. F.; Blumenhagen, K.-H.; Brandau, C.; Bräuning-Demian, A.; Chen, W.; Forstner, O.; Gao, B.; Gassner, T.; Grisenti, R. E.; Hagmann, S.; Hillenbrand, P.-M.; Indelicato, P.; Kumar, A.; Lestinsky, M.; Litvinov, Yu. A.; Petridis, N.; Schury, D.; Spillmann, U.; Trageser, C.; Trassinelli, M.; Tu, X.; Stöhlker, Th.

2017-10-01

In this work, we present a pilot experiment in the experimental storage ring (ESR) at GSI devoted to impact parameter sensitive studies of inner shell atomic processes for low-energy (heavy-) ion-atom collisions. The experiment was performed with bare and He-like xenon ions (Xe54+, Xe52+) colliding with neutral xenon gas atoms, resulting in a symmetric collision system. This choice of the projectile charge states was made in order to compare the effect of a filled K-shell with the empty one. The projectile and target X-rays have been measured at different observation angles for all impact parameters as well as for the impact parameter range of ∼35-70 fm.

Soviet Hadron Collider

NASA Astrophysics Data System (ADS)

Kotchetkov, Dmitri

2017-01-01

Rapid growth of the high energy physics program in the USSR during 1960s-1970s culminated with a decision to build the Accelerating and Storage Complex (UNK) to carry out fixed target and colliding beam experiments. The UNK was to have three rings. One ring was to be built with conventional magnets to accelerate protons up to the energy of 600 GeV. The other two rings were to be made from superconducting magnets, each ring was supposed to accelerate protons up to the energy of 3 TeV. The accelerating rings were to be placed in an underground tunnel with a circumference of 21 km. As a 3 x 3 TeV collider, the UNK would make proton-proton collisions with a luminosity of 4 x 1034 cm-1s-1. Institute for High Energy Physics in Protvino was a project leading institution and a site of the UNK. Accelerator and detector research and development studies were commenced in the second half of 1970s. State Committee for Utilization of Atomic Energy of the USSR approved the project in 1980, and the construction of the UNK started in 1983. Political turmoil in the Soviet Union during late 1980s and early 1990s resulted in disintegration of the USSR and subsequent collapse of the Russian economy. As a result of drastic reduction of funding for the UNK, in 1993 the project was restructured to be a 600 GeV fixed target accelerator only. While the ring tunnel and proton injection line were completed by 1995, and 70% of all magnets and associated accelerator equipment were fabricated, lack of Russian federal funding for high energy physics halted the project at the end of 1990s.

The conversion of CESR to operate as the Test Accelerator, CesrTA. Part 1: overview

NASA Astrophysics Data System (ADS)

Billing, M. G.

2015-07-01

Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper outlines the motivation, design and conversion of CESR to a test accelerator, CESRTA, enhanced to study such subjects as low emittance tuning methods, electron cloud (EC) effects, intra-beam scattering, fast ion instabilities as well as general improvements to beam instrumentation. While the initial studies of CESRTA focussed on questions related to the International Linear Collider (ILC) damping ring design, CESRTA is a very flexible storage ring, capable of studying a wide range of accelerator physics and instrumentation questions. This paper contains the outline and the basis for a set of papers documenting the reconfiguration of the storage ring and the associated instrumentation required for the studies described above. Further details may be found in these papers.

Accomplishments of the heavy electron particle accelerator program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, D.; Stratakis, D.; Palmer, M.

The Muon Accelerator Program (MAP) has completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of heavy lepton colliders (HLCs) from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe (more » $$\\bar{ve}$$) and $$\\bar{vμ}$$ (νμ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components have been obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and the precise physics goals become apparent.« less

Muon Sources for Particle Physics - Accomplishments of the Muon Accelerator Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, D.; Stratakis, D.; Palmer, M.

The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a μ storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of νe (ν more » $$\\bar{e}$$) and ν $$\\bar{μ}$$) (ν μ) beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent« less

ISABELLE: a progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, H

This paper discusses the ISABELLE project, which has the objective of constructing a high-energy proton colliding beam facility at Brookhaven National Laboratory. The major technical features of the intersecting storage accelerators with their projected performance are described. Application of over 1000 superconducting magnets in the two rings represents the salient characteristic of the machine. The status of the entire project, the technical progress made so far, and difficulties encountered are reviewed.

The conversion of CESR to operate as the Test Accelerator, CesrTA. Part 3: Electron cloud diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Billing, M. G.; Conway, J. V.; Crittenden, J. A.

Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper is the third in a series of four describing the conversion of CESR to themore » test accelerator, CESRTA. The first two papers discuss the overall plan for the conversion of the storage ring to an instrument capable of studying advanced accelerator physics issues [1] and the details of the vacuum system upgrades [2]. This paper focuses on the necessary development of new instrumentation, situated in four dedicated experimental regions, capable of studying such phenomena as electron clouds (ECs) and methods to mitigate EC effects. The fourth paper in this series describes the vacuum system modifications of the superconducting wigglers to accommodate the diagnostic instrumentation for the study of EC behavior within wigglers. Lastly, while the initial studies of CESRTA focused on questions related to the International Linear Collider damping ring design, CESRTA is a very versatile storage ring, capable of studying a wide range of accelerator physics and instrumentation questions.« less

The conversion of CESR to operate as the Test Accelerator, CesrTA. Part 3: Electron cloud diagnostics

DOE PAGES

Billing, M. G.; Conway, J. V.; Crittenden, J. A.; ...

2016-04-28

Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper is the third in a series of four describing the conversion of CESR to themore » test accelerator, CESRTA. The first two papers discuss the overall plan for the conversion of the storage ring to an instrument capable of studying advanced accelerator physics issues [1] and the details of the vacuum system upgrades [2]. This paper focuses on the necessary development of new instrumentation, situated in four dedicated experimental regions, capable of studying such phenomena as electron clouds (ECs) and methods to mitigate EC effects. The fourth paper in this series describes the vacuum system modifications of the superconducting wigglers to accommodate the diagnostic instrumentation for the study of EC behavior within wigglers. Lastly, while the initial studies of CESRTA focused on questions related to the International Linear Collider damping ring design, CESRTA is a very versatile storage ring, capable of studying a wide range of accelerator physics and instrumentation questions.« less

Impedance computations and beam-based measurements: A problem of discrepancy

NASA Astrophysics Data System (ADS)

Smaluk, Victor

2018-04-01

High intensity of particle beams is crucial for high-performance operation of modern electron-positron storage rings, both colliders and light sources. The beam intensity is limited by the interaction of the beam with self-induced electromagnetic fields (wake fields) proportional to the vacuum chamber impedance. For a new accelerator project, the total broadband impedance is computed by element-wise wake-field simulations using computer codes. For a machine in operation, the impedance can be measured experimentally using beam-based techniques. In this article, a comparative analysis of impedance computations and beam-based measurements is presented for 15 electron-positron storage rings. The measured data and the predictions based on the computed impedance budgets show a significant discrepancy. Three possible reasons for the discrepancy are discussed: interference of the wake fields excited by a beam in adjacent components of the vacuum chamber, effect of computation mesh size, and effect of insufficient bandwidth of the computed impedance.

Review of results from CESR (Cornell Electron Storage Ring) and DORIS (DOpple RIng Spiecher)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shibata, E.I.

1989-01-01

Selected results from e/sup +/e/sup /minus// colliding beam experiments operating in the ..sqrt..s approx. 10 GeV region are reviewed. Photon and ..pi pi.. transitions from the UPSILON(1S), UPSILON(2S), and UPSILON(3S) bound states have been used to study the spectroscopy of the b/bar b/ system. The UPSILON(4S), which decays almost exclusively to B/bar B/, has been used to search for rare exclusive decay modes of B mesons and to measure B/sup 0//bar B//sup 0/ mixing. Searches for the Higgs particle have been made in UPSILON and B decays. 43 refs., 13 figs., 2 tabs.

DAΦNE operation with electron-cloud-clearing electrodes.

PubMed

Alesini, D; Drago, A; Gallo, A; Guiducci, S; Milardi, C; Stella, A; Zobov, M; De Santis, S; Demma, T; Raimondi, P

2013-03-22

The effects of an electron cloud (e-cloud) on beam dynamics are one of the major factors limiting performances of high intensity positron, proton, and ion storage rings. In the electron-positron collider DAΦNE, namely, a horizontal beam instability due to the electron-cloud effect has been identified as one of the main limitations on the maximum stored positron beam current and as a source of beam quality deterioration. During the last machine shutdown in order to mitigate such instability, special electrodes have been inserted in all dipole and wiggler magnets of the positron ring. It has been the first installation all over the world of this type since long metallic electrodes have been installed in all arcs of the collider positron ring and are currently used during the machine operation in collision. This has allowed a number of unprecedented measurements (e-cloud instabilities growth rate, transverse beam size variation, tune shifts along the bunch train) where the e-cloud contribution is clearly evidenced by turning the electrodes on and off. In this Letter we briefly describe a novel design of the electrodes, while the main focus is on experimental measurements. Here we report all results that clearly indicate the effectiveness of the electrodes for e-cloud suppression.

Report of the New Rings Study Group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, S.D.; Dugan, G.; Marriner, J.

1987-10-19

We have taken the approach here of trying to understand both the feasibility and practicality of varied options for new rings at Fermilab, rather than trying to produce a single detailed design. In other words, this document is not a design report and should not be construed as such. Our perception of the potential needs for new rings (in order of priority) is as follows: Antiproton Storage and/or Recovery: A facility for storing up to 4 x 10/sup 12/ antiprotons is needed. Recovery of antiprotons from the collider becomes a viable option if the luminosity is indeed dominated by emittancemore » dilution rather than beam loss. New or Post-Booster: The goal here would be to inject into the existing Main Ring above transition. Improved performance of the Main Ring would be anticipated. New Main Ring: Advantages would include better emittance preservation, a faster cycle time for antiproton production, and the removal of interference/backgrounds at the B0 and D0 detectors. We discuss in this paper various scenarios based on one or more combinations of the above possibilities. 14 figs., 10 tabs.« less

CEPC-SPPC accelerator status towards CDR

NASA Astrophysics Data System (ADS)

Gao, J.

2017-12-01

In this paper we will give an introduction to the Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of the CEPC are described. On the CEPC accelerator, the optimization of parameter designs for the CEPC with different energies, machine lengths, single ring and crab-waist collision partial double ring, advanced partial double ring and fully partial double ring options, etc. have been discussed systematically, and compared. The CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The CEPC sub-systems, such as the collider main ring, booster, electron positron injector, etc. have also been introduced. The detector and the MAchine-Detector Interface (MDI) design have been briefly mentioned. Finally, the optimization design of the Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of the CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.

Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stancari, Giulio; Moens, Vince; Redaelli, Stefano

2014-07-01

Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The designmore » of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.« less

Impedance computations and beam-based measurements: A problem of discrepancy

DOE PAGES

Smaluk, Victor

2018-04-21

High intensity of particle beams is crucial for high-performance operation of modern electron-positron storage rings, both colliders and light sources. The beam intensity is limited by the interaction of the beam with self-induced electromagnetic fields (wake fields) proportional to the vacuum chamber impedance. For a new accelerator project, the total broadband impedance is computed by element-wise wake-field simulations using computer codes. For a machine in operation, the impedance can be measured experimentally using beam-based techniques. In this article, a comparative analysis of impedance computations and beam-based measurements is presented for 15 electron-positron storage rings. The measured data and the predictionsmore » based on the computed impedance budgets show a significant discrepancy. For this article, three possible reasons for the discrepancy are discussed: interference of the wake fields excited by a beam in adjacent components of the vacuum chamber, effect of computation mesh size, and effect of insufficient bandwidth of the computed impedance.« less

Impedance computations and beam-based measurements: A problem of discrepancy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smaluk, Victor

High intensity of particle beams is crucial for high-performance operation of modern electron-positron storage rings, both colliders and light sources. The beam intensity is limited by the interaction of the beam with self-induced electromagnetic fields (wake fields) proportional to the vacuum chamber impedance. For a new accelerator project, the total broadband impedance is computed by element-wise wake-field simulations using computer codes. For a machine in operation, the impedance can be measured experimentally using beam-based techniques. In this article, a comparative analysis of impedance computations and beam-based measurements is presented for 15 electron-positron storage rings. The measured data and the predictionsmore » based on the computed impedance budgets show a significant discrepancy. For this article, three possible reasons for the discrepancy are discussed: interference of the wake fields excited by a beam in adjacent components of the vacuum chamber, effect of computation mesh size, and effect of insufficient bandwidth of the computed impedance.« less

Compton backscattered collimated x-ray source

DOEpatents

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

1998-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collmated X-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

1985 Particle Accelerator Conference: Accelerator Engineering and Technology, 11th, Vancouver, Canada, May 13-16, 1985, Proceedings

NASA Astrophysics Data System (ADS)

Strathdee, A.

1985-10-01

The topics discussed are related to high-energy accelerators and colliders, particle sources and electrostatic accelerators, controls, instrumentation and feedback, beam dynamics, low- and intermediate-energy circular accelerators and rings, RF and other acceleration systems, beam injection, extraction and transport, operations and safety, linear accelerators, applications of accelerators, radiation sources, superconducting supercolliders, new acceleration techniques, superconducting components, cryogenics, and vacuum. Accelerator and storage ring control systems are considered along with linear and nonlinear orbit theory, transverse and longitudinal instabilities and cures, beam cooling, injection and extraction orbit theory, high current dynamics, general beam dynamics, and medical and radioisotope applications. Attention is given to superconducting RF structures, magnet technology, superconducting magnets, and physics opportunities with relativistic heavy ion accelerators.

TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Haipeng; Guo, Jiquan; Rimmer, Robert A.

2016-05-01

The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability.more » We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.« less

9-D polarized proton transport in the MEIC figure 8 collider ring - first steps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meot, F.; Morozov, V. S.

2015-05-03

Spin tracking studies in the MEIC figure-8 collider ion ring are presented, based on a very preliminary design of the lattice. They provide numerical illustrations of some of the aspects of the figure-8 concept, including spin-rotator based spin control, and lay out the path towards a complete spin tracking simulation of a figure-8 ring.

9-D polarized proton transport in the MEIC figure-8 collider ring: first steps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meot, F.; Thomas Jefferson National Accelerator Facility; Morozov, V. S.

2014-10-24

Spin tracking studies in the MEIC figure-8 collider ion ring are presented, based on a very preliminary design of the lattice. They provide numerical illustrations of some of the aspects of the figure-8 concept, including spin-rotator based spin control, and lay out the path towards a complete spin tracking simulation of a figure-8 ring.

Design of a High Luminosity 100 TeV Proton-Antiproton Collider

NASA Astrophysics Data System (ADS)

Oliveros Tautiva, Sandra Jimena

Currently new physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. A 10 34 cm-2 s-1 luminosity 100 TeV proton-antiproton collider is explored with 7x the energy of the LHC. The dipoles are 4.5 T to reduce cost. A proton-antiproton collider is selected as a future machine for several reasons. The cross section for many high mass states is 10 times higher in pp than pp collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per bunch crossing, because lower beam currents can produce the same rare event rates. Events are also more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller beta* for higher luminosity. To adjust to antiproton beam losses (burn rate), a Fermilab-like antiproton source would be adapted to disperse the beam into 12 different momentum channels, using electrostatic septa, to increase antiproton momentum capture 12 times. At Fermilab, antiprotons were stochastically cooled in one Debuncher and one Accumulator ring. Because the stochastic cooling time scales as the number of particles, two options of 12 independent cooling systems are presented. One electron cooling ring might follow the stochastic cooling rings for antiproton stacking. Finally antiprotons in the collider ring would be recycled during runs without leaving the collider ring, by joining them to new bunches with snap bunch coalescence and synchrotron damping. These basic ideas are explored in this work on a future 100 TeV proton-antiproton collider and the main parameters are presented.

Design of a High Luminosity 100 TeV Proton Antiproton Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveros Tuativa, Sandra Jimena

2017-04-01

Currently new physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. A 10more » $$^{\\,34}$$ cm$$^{-2}$$ s$$^{-1}$$ luminosity 100 TeV proton-antiproton collider is explored with 7$$\\times$$ the energy of the LHC. The dipoles are 4.5\\,T to reduce cost. A proton-antiproton collider is selected as a future machine for several reasons. The cross section for many high mass states is 10 times higher in $$p\\bar{p}$$ than $pp$ collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per bunch crossing, because lower beam currents can produce the same rare event rates. Events are also more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller $$\\beta^{*}$$ for higher luminosity. To adjust to antiproton beam losses (burn rate), a Fermilab-like antiproton source would be adapted to disperse the beam into 12 different momentum channels, using electrostatic septa, to increase antiproton momentum capture 12 times. At Fermilab, antiprotons were stochastically cooled in one Debuncher and one Accumulator ring. Because the stochastic cooling time scales as the number of particles, two options of 12 independent cooling systems are presented. One electron cooling ring might follow the stochastic cooling rings for antiproton stacking. Finally antiprotons in the collider ring would be recycled during runs without leaving the collider ring, by joining them to new bunches with snap bunch coalescence and synchrotron damping. These basic ideas are explored in this work on a future 100 TeV proton-antiproton collider and the main parameters are presented.« less

Lattice design for the CEPC double ring scheme

NASA Astrophysics Data System (ADS)

Wang, Yiwei; Su, Feng; Bai, Sha; Zhang, Yuan; Bian, Tianjian; Wang, Dou; Yu, Chenghui; Gao, Jie

2018-01-01

A future Circular Electron Positron Collider (CEPC) has been proposed by China with the main goal of studying the Higgs boson. Its baseline design, chosen on the basis of its performance, is a double ring scheme; an alternative design is a partial double ring scheme which reduces the budget while maintaining an adequate performance. This paper will present the collider ring lattice design for the double ring scheme. The CEPC will also work as a W and a Z factory. For the W and Z modes, except in the RF region, compatible lattices were obtained by scaling down the magnet strength with energy.

Bunch Splitting Simulations for the JLEIC Ion Collider Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satogata, Todd J.; Gamage, Randika

2016-05-01

We describe the bunch splitting strategies for the proposed JLEIC ion collider ring at Jefferson Lab. This complex requires an unprecedented 9:6832 bunch splitting, performed in several stages. We outline the problem and current results, optimized with ESME including general parameterization of 1:2 bunch splitting for JLEIC parameters.

Negative ion source development at the cooler synchrotron COSY/Jülich

NASA Astrophysics Data System (ADS)

Felden, O.; Gebel, R.; Maier, R.; Prasuhn, D.

2013-02-01

The Nuclear Physics Institute at the Forschungszentrum Jülich, a member of the Helmholtz Association, conducts experimental and theoretical basic research in the field of hadron, particle, and nuclear physics. It operates the cooler synchrotron COSY, an accelerator and storage ring, which provides unpolarized and polarized proton and deuteron beams with beam momenta of up to 3.7 GeV/c. Main activities of the accelerator division are the design and construction of the high energy storage ring HESR, a synchrotron and part of the international FAIR project, and the operation and development of COSY with injector cyclotron and ion sources. Filament driven volume sources and a charge exchange colliding beams source, based on a nuclear polarized atomic beam source, provide unpolarized and polarized H- or D- routinely for more than 6500 hours/year. Within the Helmholtz Association's initiative Accelerator Research and Development, ARD, the existing sources at COSY, as well as new sources for future programs, are investigated and developed. The paper reports about these plans, improved pulsed beams from the volume sources and the preparation of a source for the ELENA project at CERN.

Crab Waist Collision at DAFNE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milardi, C.; Alesini, D.; Biagini, M.E.

DAFNE is an accelerator complex consisting of a double ring lepton collider working at the c.m. energy of the {Phi}-resonance (1.02 GeV) and an injection system. In its original configuration the collider consisted of two independent rings, each {approx}97 m long, sharing two 10 m long interaction regions (IR1 and IR2) where the KLOE and FINUDA or DEAR detectors were respectively installed. A full energy injection system, including an S-band linac, 180 m long transfer lines and an accumulator/damping ring, provides fast and high efficiency electron positron injection also in topping-up mode during collisions. Recently the DAFNE collider has beenmore » upgraded in order to implement a new collision scheme based on large Piwinski angle and cancellation of the synchro-betatron resonances by means of electromagnetic sextupoles (Crab-Waist compensation). The novel approach has proved to be effective in improving beam-beam interaction and collider luminosity.« less

New generation electron-positron factories

NASA Astrophysics Data System (ADS)

Zobov, Mikhail

2011-09-01

In 2010 we celebrate 50 years since commissioning of the first particle storage ring ADA in Frascati (Italy) that also became the first electron-positron collider in 1964. After that date the particle colliders have increased their intensity, luminosity and energy by several orders of magnitude. Namely, because of the high stored beam currents and high rate of useful physics events (luminosity) the modern electron-positron colliders are called "factories". However, the fundamental physics has required luminosities by 1-2 orders of magnitudes higher with respect to those presently achieved. This task can be accomplished by designing a new generation of factories exploiting the potential of a new collision scheme based on the Crab Waist (CW) collision concept recently proposed and successfully tested at Frascati. In this paper we discuss the performance and limitations of the present generation electron-positron factories and give a brief overview of new ideas and collision schemes proposed for further collider luminosity increase. In more detail we describe the CW collision concept and the results of the crab waist collision tests in DAϕNE, the Italian ϕ-factory. Finally, we briefly describe most advanced projects of the next generation factories based on the CW concept: SuperB in Italy, SuperKEKB in Japan and SuperC-Tau in Russia.

Acceleration of polarized protons and deuterons in the ion collider ring of JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondratenko, A.; Kondratenko, M.; Filatov, Yu. N.

2017-07-01

The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider's lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of "interference peaks". The beam polarization dependsmore » on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stability of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.« less

Artist rendering of dust grains colliding at low speeds

NASA Technical Reports Server (NTRS)

2003-01-01

Clues to the formation of planets and planetary rings -- like Saturn's dazzling ring system -- may be found by studying how dust grains interact as they collide at low speeds. To study the question of low-speed dust collisions, NASA sponsored the COLLisions Into Dust Experiment (COLLIDE) at the University of Colorado. It was designed to spring-launch marble-size projectiles into trays of powder similar to space or lunar dust. COLLIDE-1 (1998) discovered that collisions below a certain energy threshold eject no material. COLLIDE-2 was designed to identify where the threshold is. In COLLIDE-2, scientists nudged small projectiles into dust beds and recorded how the dust splashed outward (video frame at top; artist's rendering at bottom). The slowest impactor ejected no material and stuck in the target. The faster impactors produced ejecta; some rebounded while others stuck in the target.

Fundamental Physics

NASA Image and Video Library

2003-01-22

Clues to the formation of planets and planetary rings -- like Saturn's dazzling ring system -- may be found by studying how dust grains interact as they collide at low speeds. To study the question of low-speed dust collisions, NASA sponsored the COLLisions Into Dust Experiment (COLLIDE) at the University of Colorado. It was designed to spring-launch marble-size projectiles into trays of powder similar to space or lunar dust. COLLIDE-1 (1998) discovered that collisions below a certain energy threshold eject no material. COLLIDE-2 was designed to identify where the threshold is. In COLLIDE-2, scientists nudged small projectiles into dust beds and recorded how the dust splashed outward (video frame at top; artist's rendering at bottom). The slowest impactor ejected no material and stuck in the target. The faster impactors produced ejecta; some rebounded while others stuck in the target.

High Luminosity 100 TeV Proton-Antiproton Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveros, S. J.; Acosta, J. G.; Cremaldi, L. M.

2016-10-01

The energy scale for new physics is known to be in the multi-TeV range, signaling the potential need for a collider beyond the LHC. Amore » $$10^{34}$$ cm$$^{-2}$$ s$$^{-1}$$ luminosity 100 TeV proton-antiproton collider is explored. Prior engineering studies for 233 and 270 km circumference tunnels were done for Illinois dolomite and Texas chalk signaling manageable tunneling costs. At a $$p\\bar{p}$$ the cross section for high mass states is of order 10x higher with antiproton collisions, where antiquarks are directly present rather than relying on gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets, because lower beam currents can produce the same rare event rates. In our design the increased momentum acceptance (11 $$\\pm$$ 2.6 GeV/c) in a Fermilab-like antiproton source is used with septa to collect 12x more antiprotons in 12 channels. For stochastic cooling, 12 cooling systems would be used, each with one debuncher/momentum equalizer ring and two accumulator rings. One electron cooling ring would follow. Finally antiprotons would be recycled during runs without leaving the collider ring, by joining them to new bunches with synchrotron damping.« less

The Birth of Lepton Colliders in Italy and the United States

NASA Astrophysics Data System (ADS)

Paris, Elizabeth

2003-04-01

In 1960 the highest center-of-mass energies in particle physics were being achieved via proton synchrotrons utilizing stationary targets. However, efforts were already underway to challenge this hegemony. In addition to Soviet work in Novosibirsk, groups at Stanford University in California and at the Frascati National Laboratories near Rome each had begun original investigation towards one particular type of challenger: colliding beam storage rings. For the group in California, the accomplishment involved creating the potential for feasible experiments. The energetic advantages of the colliding beam configuration had long been accepted - together with its impossibility for realization. The builders of the Princeton-Stanford machine feel that creating usable beams and a reasonable reaction rate is what stood between this concept and its glorious future. For the European builders of AdA, however, the beauty emerges from recognizing the enormous potential inherent in electron-positron annihilations. At least as important for the rise of electron-positron colliders, though, is the role of both of these projects as cultural firsts -- as places where particular sets of physicists got their feet wet associating with beams and beam problems and with the many individuals who were addressing beam problems. The Princeton-Stanford Collider provided experience which its builders would use to move on, functioning as both a technological and political platform for creating what would eventually become SPEAR. For the Roman group, the pursuit of AdA encouraged investigation which applied equally well to their next machine, Adone.

Gauge bosons and heavy quarks: Proceedings of Summer Institute on Particle Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hawthorne, J.F.

1991-01-01

This report contains papers on the following topics: Z decays and tests of the standard model; future possibilities for LEP; studies of the interactions of electroweak gauge bosons; top quark topics; the next linear collider; electroweak processes in hadron colliders; theoretical topics in B-physics; experimental aspects of B-physics; B-factory storage ring design; rare kaon decays; CP violation in K{sup 0} decays at CERN; recent K{sup 0} decay results from Fermilab E-731; results from LEP on heavy quark physics; review of recent results on heavy flavor production; weak matrix elements and the determination of the weak mixing angles; recent results frommore » CLEO I and a glance at CLEO II data; recent results from ARGUS; neutrino lepton physics with the CHARM 2 detector; recent results from the three TRISTAN experiments; baryon number violation at high energy in the standard model: fact or fiction New particle searches at LEP; review of QCD at LEP; electroweak interactions at LEP; recent results on W physics from the UA2 experiment at the CERN {rho}{bar {rho}} collider; B physics at CDF; and review of particle astrophysics.« less

Operation of the 56 MHz superconducting RF cavity in RHIC during run 14

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.

2015-09-11

A 56 MHz superconducting RF cavity was designed and installed in the Relativistic Heavy Ion Collider (RHIC). It is the first superconducting quarter wave resonator (QWR) operating in a high-energy storage ring. We discuss herein the cavity operation with Au+Au collisions, and with asymmetrical Au+He3 collisions. The cavity is a storage cavity, meaning that it becomes active only at the energy of experiment, after the acceleration cycle is completed. With the cavity at 300 kV, an improvement in luminosity was detected from direct measurements, and the bunch length has been reduced. The uniqueness of the QWR demands an innovative designmore » of the higher order mode dampers with high-pass filters, and a distinctive fundamental mode damper that enables the cavity to be bypassed during the acceleration stage.« less

The Simpsons program 6-D phase space tracking with acceleration

NASA Astrophysics Data System (ADS)

Machida, S.

1993-12-01

A particle tracking code, Simpsons, in 6-D phase space including energy ramping has been developed to model proton synchrotrons and storage rings. We take time as the independent variable to change machine parameters and diagnose beam quality in a quite similar way as real machines, unlike existing tracking codes for synchrotrons which advance a particle element by element. Arbitrary energy ramping and rf voltage curves as a function of time are read as an input file for defining a machine cycle. The code is used to study beam dynamics with time dependent parameters. Some of the examples from simulations of the Superconducting Super Collider (SSC) boosters are shown.

Acceleration of polarized protons and deuterons in the ion collider ring of JLEIC

NASA Astrophysics Data System (ADS)

Kondratenko, A. M.; Kondratenko, M. A.; Filatov, Yu N.; Derbenev, Ya S.; Lin, F.; Morozov, V. S.; Zhang, Y.

2017-07-01

The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider’s lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of “interference peaks”. The beam polarization depends on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stability of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.

Thermal issues at the SSC

NASA Technical Reports Server (NTRS)

Ranganathan, Raj P.; Dao, Bui V.

1992-01-01

A variety of heat transfer problems arise in the design of the Superconducting Super Collider (SSC). One class of problems is to minimize heat leak from the ambient to the SSC rings, since the rings contain superconducting magnets maintained at a temperature of 4 K. Another arises from the need to dump the beam of protrons (traveling around the SSC rings) on to absorbers during an abort of the collider. Yet another category of problems is the cooling of equipment to dissipate the heat generated during operation. An overview of these problems and sample heat transfer results are given in this paper.

Study of Electron Polarization Dynamics in the JLEIC at Jlab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Fanglei; Derbenev, Yaroslav; Morozov, Vasiliy

The design of an electron polarization scheme in the Jefferson Lab Electron-Ion Collider (JLEIC) aims to attain a high longitudinal electron polarization (over 70%) at collision points as required by the nuclear physics program. Comprehensive strategies for achieving this goal have been considered and developed including injection of highly polarized electrons from CEBAF, mechanisms for manipulation and preservation of the polarization in the JLEIC collider ring and measurement of the electron polarization. In particular, maintaining a sufficiently long polarization lifetime is crucial for accumulation of adequate experimental statistics. The chosen electron polarization configuration, based on the unique figure-8 geometry ofmore » the ring, removes the electron spin-tune energy dependence. This significantly simplifies the control of the electron polarization and suppresses the synchrotron sideband resonances. This paper reports recent studies and simulations of the electron polarization dynamics in the JLEIC electron collider ring.« less

European organization for nuclear research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoenbacher, H.; Tavlet, M.

1987-09-10

The CERN Intersecting Storage Rings (ISR) operated from 1971 to 1984. During that time high-energy physics experiments were carried out with 30 GeV colliding proton beams. At the end of this period the machine was decommissioned and dismantled. This involved the movement of about 1000 machine elements, e.g., magnets, vacuum pumps, rf cavities, etc., 2500 racks, 7000 shielding blocks, 3500 km of cables and 7 km of beam piping. All these items were considered to be radioactive until the contrary was proven. They were then sorted, either for storage and reuse or for radioactive or non-radioactive waste. The paper describesmore » the radiation protection surveillance of this project which lasted for five months. It includes the radiation protection standards, the control of personnel and materials, typical radioactivity levels and isotopes, as well as final cleaning and decommissioning of an originally restricted radiation area to a free accessible area.« less

The magnet system of the Relativistic Heavy Ion Collider (RHIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, A.; Anerella, M.; Cozzolino, J.

1995-07-01

The Relativistic Heavy Ion Collider now under construction at Brookhaven National Laboratory (BNL) is a colliding ring accelerator to be completed in 1999. Through collisions of heavy ions it is hoped to observe the creation of matter at extremely high temperatures and densities, similar to what may have occurred in the original ``Big Bang.`` The collider rings will consist of 1740 superconducting magnet elements. Some of elements are being manufactured by industrial partners (Northrop Grumman and Everson Electric). Others are being constructed or assembled at BNL. A description is given of the magnet designs, the plan for manufacturing and testmore » results. In the manufacturing of the magnets, emphasis has been placed on uniformity of their performance and on quality. Results so far indicate that this emphasis has been very successful.« less

The magnet system of the Relativistic Heavy Ion Collider (RHIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, A.; Anerella, M.; Cozzolino, J.

1996-07-01

The Relativistic Heavy Ion Collider now under construction at Brookhaven National Laboratory (BNL) is a colliding ring accelerator to be completed in 1999. Through collisions of heavy ions it is hoped to observe the creation of matter at extremely high temperatures and densities, similar to what may have occurred in the original ``Big Bang``. The collider rings will consist of 1,740 superconducting magnet elements. Some of these elements are being manufactured by industrial partners (Northrop Grumman and Everson Electric). Others are being constructed or assembled at BNL. A description is given of the magnet designs, the plan for manufacturing andmore » test results. In the manufacturing of the magnets, emphasis has been placed on uniformity of their performance and on quality. Results so far indicate that this emphasis has been very successful.« less

Damping Ring R&D at CESR-TA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, David L.

2015-01-23

Accelerators that collide high energy beams of matter and anti-matter are essential tools for the investigation of the fundamental constituents of matter, and the search for new forms of matter and energy. A “Linear Collider” is a machine that would bring high energy and very compact bunches of electrons and positrons (anti-electrons) into head-on collision. Such a machine would produce (among many other things) the newly discovered Higgs particle, enabling a detailed study of its properties. Among the most critical and challenging components of a linear collider are the damping rings that produce the very compact and intense beams ofmore » electrons and positrons that are to be accelerated into collision. Hot dilute particle beams are injected into the damping rings, where they are compressed and cooled. The size of the positron beam must be reduced more than a thousand fold in the damping ring, and this compression must be accomplished in a fraction of a second. The cold compact beams are then extracted from the damping ring and accelerated into collision at high energy. The proposed International Linear Collider (ILC), would require damping rings that routinely produce such cold, compact and intense beams. The goal of the Cornell study was a credible design for the damping rings for the ILC. Among the technical challenges of the damping rings; the development of instrumentation that can measure the properties of the very small beams in a very narrow window of time, and mitigation of the forces that can destabilize the beams and prevent adequate cooling, or worse lead to beam loss. One of the most pernicious destabilizing forces is due to the formation of clouds of electrons in the beam pipe. The electron cloud effect is a phenomenon in particle accelerators in which a high density of low energy electrons, build up inside the vacuum chamber. At the outset of the study, it was anticipated that electron cloud effects would limit the intensity of the positron ring, and that an instability associated with residual gas in the beam pipe would limit the intensity of the electron ring. It was also not clear whether the required very small beam size could be achieved. The results of this study are important contributions to the design of both the electron and positron damping rings in which all of those challenges are addressed and overcome. Our findings are documented in the ILC Technical Design Report, a document that represents the work of an international collaboration of scientists. Our contributions include design of the beam magnetic optics for the 3 km circumference damping rings, the vacuum system and surface treatments for electron cloud mitigation, the design of the guide field magnets, design of the superconducting damping wigglers, and new detectors for precision measurement of beam properties. Our study informed the specification of the basic design parameters for the damping rings, including alignment tolerances, magnetic field errors, and instrumentation. We developed electron cloud modelling tools and simulations to aid in the interpretation of the measurements that we carried out in the Cornell Electron-positron Storage Ring (CESR). The simulations provide a means for systematic extrapolation of our measurements at CESR to the proposed ILC damping rings, and ultimately to specify how the beam pipes should be fabricated in order to minimize the effects of the electron cloud. With the conclusion of this study, the design of the essential components of the damping rings is complete, including the development and characterization (with computer simulations) of the beam optics, specification of techniques for minimizing beam size, design of damping ring instrumentation, R&D into electron cloud suppression methods, tests of long term durability of electron cloud coatings, and design of damping ring vacuum system components.« less

COLLIDE-2: Collisions Into Dust Experiment-2

NASA Technical Reports Server (NTRS)

Colwell, Joshua E.

2002-01-01

The Collisions Into Dust Experimental (COLLIDE-2) was the second flight of the COLLIDE payload. The payload performs six low-velocity impact experiments to study the collisions that are prevalent in planetary ring systems and in the early stages of planet formation. Each impact experiment is into a target of granular material, and the impacts occur at speeds between 1 and 100 cm/s in microgravity and in a vacuum. The experiments are recorded on digital videotape which is later analyzed. During the period of performance a plan was developed to address some of the technical issues that prevented the first flight of COLLIDE from being a complete success, and also to maximize the scientific return based on the science results from the first flight. The experiment was modified following a series of reviews of the design plan, and underwent extensive testing. The data from the experiment show that the primary goal of identifying transition regimes for low-velocity impacts based on cratering versus accretion was achieved. Following a brief period of storage, the experiment flew regimes for low-velocity impacts based on cratering versus accretion was achieved. as a Hitchhiker payload on the MACH-1 Hitchhiker bridge on STS-108 in December 2001. These data have been analyzed and submitted for publication. That manuscript is attached to this report. The experiment was retrieved in January 2002, and all six impact experiments functioned nominally. Preliminary results were reported at the Lunar and Planetary Science Conference.

Electron gun jitter effects on beam bunching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, M. S.; Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk; Centre for High Energy Physics, University of the Punjab, Lahore 45590

For routine operation of Beijing Electron Positron Collider II (BEPCII) linac, many factors may affect the beam bunching process directly or indirectly. We present the measurements and analyses of the gun timing jitter, gun high voltage jitter, and beam energy at the exit of the standard acceleration section of the linac quantitatively. Almost 80 mV and more than 200 ps of gun high voltage and time jitters have ever been measured, respectively. It was analyzed that the gun timing jitter produced severe effects on beam energy than the gun high voltage jitter, if the timing jitter exceeded 100 ps whichmore » eventually deteriorates both the beam performance and the injection rate to the storage ring.« less

The Physics of Beams: The Andrew Sessler Symposium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barletta, W.A.

1996-03-01

These proceedings represent papers presented at the Andrew Sessler Symposium held at the Lawrence Berkeley National Laboratory in honor of Andrew Sessler{close_quote}s over forty years of major scientific contributions to accelerator and beam physics as well as in celebration of his 65th birthday. The symposium was sponsored by the United States Department of Energy. The topics discussed include linear colliders, past history and future speculations, ELOISATRON at 100 TeV beam, manipulating charged particle beams by means of plasma and collective instabilities in accelerator and storage rings. There were 10 papers presented and 8 have been abstracted for the Energy Sciencemore » and Technology database.(AIP)« less

Experimental Measurements of the Secondary Electron Yield in the Experimental Measurement of the Secondary Electron Yield in the PEP-II Particle Accelerator Beam Line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pivi, M.T.F.; Collet, G.; King, F.

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders (LC) such as ILC and CLIC. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation of the secondary electron yield of technical surface materials and coatings under themore » effect of ion, electron and photon conditioning in situ in the beam line; (ii) chambers with grooves in a straight magnetic-free section; and (iii) coated chambers in a dedicated newly installed 4-magnet chicane to study mitigations in a magnetic field region. In this paper, we describe the ongoing R&D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction of the secondary electron yield due to in situ conditioning.« less

Exploration of a High Luminosity 100 TeV Proton Antiproton Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveros, Sandra J.; Summers, Don; Cremaldi, Lucien

New physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. We explore a 10more » $$^{\\,34}$$ cm$$^{-2}$$ s$$^{-1}$$ luminosity, 100 TeV $$p\\bar{p}$$ collider with 7$$\\times$$ the energy of the LHC but only 2$$\\times$$ as much NbTi superconductor, motivating the choice of 4.5 T single bore dipoles. The cross section for many high mass states is 10 times higher in $$p\\bar{p}$$ than $pp$ collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per beam crossing, because lower beam currents can produce the same rare event rates. Events are more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller $$\\beta^{*}$$ for higher luminosity. A Fermilab-like $$\\bar p$$ source would disperse the beam into 12 momentum channels to capture more antiprotons. Because stochastic cooling time scales as the number of particles, 12 cooling ring sets would be used. Each set would include phase rotation to lower momentum spreads, equalize all momentum channels, and stochastically cool. One electron cooling ring would follow the stochastic cooling rings. Finally antiprotons would be recycled during runs without leaving the collider ring by joining them to new bunches with synchrotron damping.« less

Participation in the ARGUS experiment at the DORIS collider at DESY, Hamburg, Germany

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darden, C.

1986-03-27

Progress reported for 1985 includes publishing final results for investigation of F mesons. Particle decays were sought including a gamma line at 9.46 GeV. One such decay was Upsilon(1S)..--> gamma..H/sup 0/. A search for fractionally charged particles is reported. The muon pair branching ratio was determined for decays of the Upsilon(2S). Six anti-deuterons were seen in a data sample of over 720,000 electron-positron annihilation events. A clear D/sup 0/ signal was seen in the K/sup +/K/sup -/ channel. Results were obtained for the radiative transitions from the Upsilon(2S) to the 1/sup 3/P states of the banti-b system. Fifteen events weremore » also seen which were interpreted to be the color suppressed decay of a B meson to J/psi. A new upper limit was set for the mass of the tau neutrino. A CAMAC booster was used to reduce dead time in the experiment. New preamplifiers raised the vertex drift chambers enough above the electromagnetic noise of the storage ring that it was no longer a problem. The performance of the inner compensation coils, storage ring, and main drift chamber are reported, as well as the time of flight, shower, and muon counters. (LEW)« less

A Study of Single Pass Ion Effects at the ALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrd, J.M.; Thomson, J.; /LBL, Berkeley

2011-09-13

We report the results of experiments on a 'fast beam-ion instability' at the Advanced Light Source (ALS). This ion instability, which can arise even when the ions are not trapped over multiple beam passages, will likely be important for many future accelerators. In our experiments, we filled the ALS storage ring with helium gas, raising the pressure approximately two orders of magnitude above the nominal pressure. With gaps in the bunch train large enough to avoid conventional (multi-turn) ion trapping, we observed a factor of 2-3 increase in the vertical beam size along with coherent beam oscillations which increased alongmore » the bunch train. Ion trapping has long been recognized as a potential limitation in electron storage rings. The ions, generated by beam-gas collisions, become trapped in the negative potential of the beam and accumulate over multiple beam passages. The trapped ions are then observed to cause a number of deleterious effects such as an increasing beam phase space, a broadening and shifting of the beam transverse oscillation frequencies (tunes), collective beam instabilities, and beam lifetime reductions. All of these effects are of concern for the next generation of accelerators, such as the B-factories or damping rings for future linear colliders, which will store high beam currents with closely spaced bunches and ultra-low beam emittances. One of the standard solutions used to prevent ion trapping is to include a gap in the bunch train which is long compared to the bunch spacing. In this case, the ions are first strongly-focused by the passing electron bunches and then over-focused in the gap. With a sufficiently large gap, the ions can be driven to large amplitudes where they form a diffuse halo and do not affect the beam. In this paper, we describe experiments that study a new regime of transient ion instabilities predicted to arise in future electron storage rings, and linacs with bunch trains. These future rings and linacs, which will be operated with higher beam currents, small transverse beam emittances, and long bunch trains, will use ion clearing gaps to prevent conventional ion trapping. But, while the ion clearing gap may suppress the conventional ion instabilities, it will not suppress a transient beam-ion instability where ions generated and trapped during the passage of a single train lead to a fast instability. While both conventional and transient ion instabilities have the same origin, namely ions produced by the beam, they have different manifestations and, more importantly, the new transient instability can arise even after the conventional ion instability is cured. This new instability is called the 'Fast Beam-Ion Instability' (FBII). In many future rings, the FBII is predicted to have very fast growth rates, much faster than the damping rates of existing and proposed transverse feedback systems, and thus is a potential limitation. To study the FBII, we performed experiments at the ALS, a 1.5 GeV electron storage ring. At the nominal ALS pressure of about 0.24 nTorr, the FBII is not evident. To study the instability, we intentionally added helium gas to the storage-ring vacuum system until the residual gas pressure was increased about 80 nTorr. This brought the predicted growth rate of the instability at least an order of magnitude above the growth rate of conventional multibunch instabilities driven by the RF cavities and above the damping rate of the transverse feedback system (TFB) in the ALS and, thereby, established conditions very similar to those in a future storage ring. We then filled the ring with a relatively short train of bunches, suppressing conventional ion instabilities. In the following, we will first briefly describe This paper describes the experiment and results in more detail.« less

The Coming Revolutions in Particle Physics

ScienceCinema

Quigg, Chris

2017-12-09

Wonderful opportunities await particle physics over the next decade, with new instruments and experiments poised to explore the frontiers of high energy, infinitesimal distances, and exquisite rarity. We look forward to the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. We suspect that the detection of proton decay is only a few orders of magnitude away in sensitivity. Astronomical observations should help to tell us what kinds of matter and energy make up the universe. We might even learn to read experiment for clues about the dimensionality of spacetime. If we are inventive enough, we may be able to follow this rich menu with the physics opportunities offered by a linear electron-positron collider and a (muon storage ring) neutrino factory. I expect a remarkable flowering of experimental particle physics, and of theoretical physics that engages with experiment.

Design and system integration of the superconducting wiggler magnets for the Compact Linear Collider damping rings

NASA Astrophysics Data System (ADS)

Schoerling, Daniel; Antoniou, Fanouria; Bernhard, Axel; Bragin, Alexey; Karppinen, Mikko; Maccaferri, Remo; Mezentsev, Nikolay; Papaphilippou, Yannis; Peiffer, Peter; Rossmanith, Robert; Rumolo, Giovanni; Russenschuck, Stephan; Vobly, Pavel; Zolotarev, Konstantin

2012-04-01

To achieve high luminosity at the collision point of the Compact Linear Collider (CLIC), the normalized horizontal and vertical emittances of the electron and positron beams must be reduced to 500 and 4 nm before the beams enter the 1.5 TeV linear accelerators. An effective way to accomplish ultralow emittances with only small effects on the electron polarization is using damping rings operating at 2.86 GeV equipped with superconducting wiggler magnets. This paper describes a technical design concept for the CLIC damping wigglers.

Multiparticle Simulation of Intrabeam Scattering for SuperB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biagini, M.; Boscolo, M.; Demma, T.

In this communication we present the structure of a multiparticle tracking code to investigate intrabeam scattering effects in low emittance colliders. Simulation results obtained with particular reference to the SuperB parameters are compared with those of conventional IBS theories.and with those of a novel semi-analythical model able to predict IBS effect in terms of emittance growths. Intrabeam scattering (IBS) is associated with multiple small angle scattering events leading to emittance growth. In most electron storage rings, the growth rates arising from IBS are usually much longer than damping times due to synchrotron radiation, and its effect is not observed. However,more » IBS growth rates increase with bunch charge density, and for machines such as SuperB, that operate with high bunch charges and very low emittances, the IBS growth rates can be large enough to observe significant emittance increase. Several formalisms have been developed for calculating IBS growth rates in storage rings, notably those by Piwinski, Bjorken and Mtingwa, and their high energy approximations. Calculations show that IBS should be manageable in both SuperB rings. However these analytical models, based on Gaussian bunch distributions, cannot investigate some interesting aspects of IBS such as its impact during the damping process and its effect on the beam distribution. We developed a multiparticle tracking code, based on the Zenkevich-Bolshakov algorithm, to investigate these effects. In this communication we present the structure of the code and some simulation results obtained with particular reference to the SuperB parameters. Simulation results are compared with those of conventional IBS theories.« less

Error Correction for the JLEIC Ion Collider Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Guohui; Morozov, Vasiliy; Lin, Fanglei

2016-05-01

The sensitivity to misalignment, magnet strength error, and BPM noise is investigated in order to specify design tolerances for the ion collider ring of the Jefferson Lab Electron Ion Collider (JLEIC) project. Those errors, including horizontal, vertical, longitudinal displacement, roll error in transverse plane, strength error of main magnets (dipole, quadrupole, and sextupole), BPM noise, and strength jitter of correctors, cause closed orbit distortion, tune change, beta-beat, coupling, chromaticity problem, etc. These problems generally reduce the dynamic aperture at the Interaction Point (IP). According to real commissioning experiences in other machines, closed orbit correction, tune matching, beta-beat correction, decoupling, andmore » chromaticity correction have been done in the study. Finally, we find that the dynamic aperture at the IP is restored. This paper describes that work.« less

Design Considerations for High Energy Electron -- Positron Storage Rings

DOE R&D Accomplishments Database

Richter, B.

1966-11-01

High energy electron-positron storage rings give a way of making a new attack on the most important problems of elementary particle physics. All of us who have worked in the storage ring field designing, building, or using storage rings know this. The importance of that part of storage ring work concerning tests of quantum electrodynamics and mu meson physics is also generally appreciated by the larger physics community. However, I do not think that most of the physicists working tin the elementary particle physics field realize the importance of the contribution that storage ring experiments can make to our understanding of the strongly interacting particles. I would therefore like to spend the next few minutes discussing the sort of things that one can do with storage rings in the strongly interacting particle field.

Design of a 6 TeV muon collider

DOE PAGES

Wang, M-H.; Nosochkov, Y.; Cai, Y.; ...

2016-09-09

Here, a preliminary design of a muon collider ring with the center of mass (CM) energy of 6 TeV is presented. The ring circumference is 6.3 km, and themore » $$\\beta$$ functions at collision point are 1 cm in each plane. The ring linear optics, the non-linear chromaticity compensation in the Interaction Region (IR), and the additional non-linear orthogonal correcting knobs are described. Magnet specifications are based on the maximum pole-tip field of 20T in dipoles and 15T in quadrupoles. Careful compensation of the non-linear chromatic and amplitude dependent effects provide a sufficiently large dynamic aperture for the momentum range of up to $$\\pm$$0.5% without considering magnet errors.« less

SuperB Progress Report for Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biagini, M.E.; Boni, R.; Boscolo, M.

2012-02-14

This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around themore » world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and national laboratories. In Italy these may include INFN Frascati and the University of Pisa, in the United States SLAC, LBNL, BNL and several universities, in France IN2P3, LAPP, and Grenoble, in Russia BINP, in Poland Krakow University, and in the UK the Cockcroft Institute. The construction time for this collider is a total of about four years. The new tunnel can be bored in about a year. The new accelerator components can be built and installed in about 4 years. The shipping of components from PEP-II at SLAC to Italy will take about a year. A new linac and damping ring complex for the injector for the rings can be built in about three years. The commissioning of this new accelerator will take about a year including the new electron and positron sources, new linac, new damping ring, new beam transport lines, two new collider rings and the Interaction Region. The new particle physics detector can be commissioned simultaneously with the accelerator. Once beam collisions start for particle physics, the luminosity will increase with time, likely reaching full design specifications after about two to three years of operation. After construction, the operation of the collider will be the responsibility of the Italian INFN governmental agency. The intent is to run this accelerator about ten months each year with about one month for accelerator turn-on and nine months for colliding beams. The collider will need to operate for about 10 years to provide the required 50 ab{sup -1} requested by the detector collaboration. Both beams as anticipated in this collider will have properties that are excellent for use as sources for synchrotron radiation (SR). The expected photon properties are comparable to those of PETRA-3 or NSLS-II. The beam lines and user facilities needed to carry out this SR program are being investigated.« less

Design of beam optics for the future circular collider e + e - collider rings

DOE PAGES

Oide, Katsunobu; Aiba, M.; Aumon, S.; ...

2016-11-21

A beam optics scheme has been designed for the future circular collider- e +e - (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [P. Raimondi, D. Shatilov, and M. Zobov, arXiv:physics/0702033; P. Raimondi, M. Zobov, and D. Shatilov, in Proceedings of the 22nd Particle Accelerator Conference, PAC-2007, Albuquerque, NM (IEEE, New York, 2007), p. TUPAN037.] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system withoutmore » additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called “tapering” of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [A. Chancé et al., Proceedings of IPAC’16, 9–13 May 2016, Busan, Korea, TUPMW020 (2016).] as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than ±2% has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this study is a step toward a full conceptual design for the collider. Finally, a number of issues have been identified for further study.« less

Design of beam optics for the future circular collider e + e - collider rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oide, Katsunobu; Aiba, M.; Aumon, S.

A beam optics scheme has been designed for the future circular collider- e +e - (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [P. Raimondi, D. Shatilov, and M. Zobov, arXiv:physics/0702033; P. Raimondi, M. Zobov, and D. Shatilov, in Proceedings of the 22nd Particle Accelerator Conference, PAC-2007, Albuquerque, NM (IEEE, New York, 2007), p. TUPAN037.] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system withoutmore » additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called “tapering” of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [A. Chancé et al., Proceedings of IPAC’16, 9–13 May 2016, Busan, Korea, TUPMW020 (2016).] as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than ±2% has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this study is a step toward a full conceptual design for the collider. Finally, a number of issues have been identified for further study.« less

Design of beam optics for the future circular collider e+e- collider rings

NASA Astrophysics Data System (ADS)

Oide, K.; Aiba, M.; Aumon, S.; Benedikt, M.; Blondel, A.; Bogomyagkov, A.; Boscolo, M.; Burkhardt, H.; Cai, Y.; Doblhammer, A.; Haerer, B.; Holzer, B.; Jowett, J. M.; Koop, I.; Koratzinos, M.; Levichev, E.; Medina, L.; Ohmi, K.; Papaphilippou, Y.; Piminov, P.; Shatilov, D.; Sinyatkin, S.; Sullivan, M.; Wenninger, J.; Wienands, U.; Zhou, D.; Zimmermann, F.

2016-11-01

A beam optics scheme has been designed for the future circular collider-e+e- (FCC-ee). The main characteristics of the design are: beam energy 45 to 175 GeV, 100 km circumference with two interaction points (IPs) per ring, horizontal crossing angle of 30 mrad at the IP and the crab-waist scheme [P. Raimondi, D. Shatilov, and M. Zobov, arXiv:physics/0702033; P. Raimondi, M. Zobov, and D. Shatilov, in Proceedings of the 22nd Particle Accelerator Conference, PAC-2007, Albuquerque, NM (IEEE, New York, 2007), p. TUPAN037.] with local chromaticity correction. The crab-waist scheme is implemented within the local chromaticity correction system without additional sextupoles, by reducing the strength of one of the two sextupoles for vertical chromatic correction at each side of the IP. So-called "tapering" of the magnets is applied, which scales all fields of the magnets according to the local beam energy to compensate for the effect of synchrotron radiation (SR) loss along the ring. An asymmetric layout near the interaction region reduces the critical energy of SR photons on the incoming side of the IP to values below 100 keV, while matching the geometry to the beam line of the FCC proton collider (FCC-hh) [A. Chancé et al., Proceedings of IPAC'16, 9-13 May 2016, Busan, Korea, TUPMW020 (2016).] as closely as possible. Sufficient transverse/longitudinal dynamic aperture (DA) has been obtained, including major dynamical effects, to assure an adequate beam lifetime in the presence of beamstrahlung and top-up injection. In particular, a momentum acceptance larger than ±2 % has been obtained, which is better than the momentum acceptance of typical collider rings by about a factor of 2. The effects of the detector solenoids including their compensation elements are taken into account as well as synchrotron radiation in all magnets. The optics presented in this paper is a step toward a full conceptual design for the collider. A number of issues have been identified for further study.

Static beam-based alignment for the Ring-To-Main-Linac of the Compact Linear Collider

NASA Astrophysics Data System (ADS)

Han, Y.; Latina, A.; Ma, L.; Schulte, D.

2017-06-01

The Compact Linear Collider (CLIC) is a future multi-TeV collider for the post-Large Hadron Collider era. It features high-gradient acceleration and ultra-low emittance to achieve its ambitious goals of high collision energy and peak luminosity. Beam-based alignment (BBA) techniques are mandatory for CLIC to preserve the ultra-low emittances from the damping rings to the interaction point. In this paper, a detailed study of BBA techniques has been carried out for the entire 27 km long ``Ring-To-Main-Linac'' (RTML) section of the CLIC, to correct realistic static errors such as element position offsets, angle, magnetic strength and dynamic magnetic centre shifts. The correction strategy is proved to be very effective and leads to a relaxation of the pre-alignment tolerances for the component installation in the tunnel. This is the first time such a large scale and complex lattice has been corrected to match the design budgets. The techniques proposed could be applied to similarly sized facilities, such as the International Linear Collider, where a similar RTML section is used, or free-electron lasers, which, being equipped with linacs and bunch compressors, present challenges similar to those of the CLIC RTML. Moreover, a new technique is investigated for the emittance tuning procedure: the direct measurement of the interactions between the beams and a set of a few consecutive laser wires. The speed of this technique can be faster comparing to the traditional techniques based on emittance reconstructed from beam size measurements at several positions.

Bruno Touschek: particle physicist and father of the e+e- collider

NASA Astrophysics Data System (ADS)

Bonolis, Luisa; Pancheri, Giulia

2011-07-01

This article gives a brief outline of the life and works of the Austrian physicist Bruno Touschek, who conceived and, 50 years ago, brought to completion the construction of AdA, the first electron-positron storage ring. The events which led to the approval of the AdA project and the Franco-Italian collaboration which confirmed the feasibility of electron-positron storage rings will be recalled. We shall illustrate Bruno Touschek's formation both as a theoretical physicist and as an expert in particle accelerators during the period between the time he had to leave the Vienna Staatgymnasium in 1938, because of his Jewish origin from the maternal side, until he arrived in Italy in the early 1950s and, in 1960, proposed to build AdA, in Frascati. The events which led to Touschek's collaboration with Rolf Widerøe in the construction of the first European betatron will be described. The article will make use of a number of unpublished as well as previously unknown documents, which include an early correspondence with Arnold Sommerfeld and Bruno Touschek's letters to his family in Vienna from Italy, Germany and Great Britain. The impact of Touschek's work on students and collaborators from University of Rome will be illustrated through his work on QED infrared radiative corrections to high energy e + e - experiments and the book Meccanica Statistica.

Ion related problems for the XLS ring

NASA Astrophysics Data System (ADS)

Bozoki, Eva S.; Halama, Henry

1991-10-01

The electron beam in a storage ring collides with the residual gas in the vacuum chamber. As a consequence, low velocity positive ions are produced and trapped in the potential well of the electron beam. They perform stable or unstable oscillations around the beam under the repetitive Coulomb force of the bunches. If not cleared, the captured ions can lead to partial or total neutralization of the beam, causing both a decrease of lifetime and a change in the vertical tunes as well as an increase in the tune spread. It can also cause coherent and incoherent transverse instabilities. An electrostatic clearing electrodes system was designed to keep the neutralization below a desired limit. The location and the geometry of the clearing electrodes as well as the applied clearing voltage is based on the study of the ion production rate, longitudinal velocity of ions in field-free regions and in the dipoles, beam self-electric field, beam potential, critical mass for ion capture in the bunched beam and the bounce frequencies of the ions, tune shift and pressure rise due to trapped ions.

Neutron dosimetry at a high-energy electron-positron collider

NASA Astrophysics Data System (ADS)

Bedogni, Roberto

Electron-positron colliders with energy of hundreds of MeV per beam have been employed for studies in the domain of nuclear and sub-nuclear physics. The typical structure of such a collider includes an LINAC, able to produce both types of particles, an accumulator ring and a main ring, whose diameter ranges from several tens to hundred meters and allows circulating particle currents of several amperes per beam. As a consequence of the interaction of the primary particles with targets, shutters, structures and barriers, a complex radiation environment is produced. This paper addresses the neutron dosimetry issues associated with the operation of such accelerators, referring in particular to the DAΦ NE complex, operative since 1997 at INFN-Frascati National Laboratory (Italy). Special attention is given to the active and passive techniques used for the spectrometric and dosimetric characterization of the workplace neutron fields, for radiation protection dosimetry purposes.

Low Emittance Tuning Studies for SuperB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liuzzo, Simone; /INFN, Pisa; Biagini, Maria

2012-07-06

SuperB[1] is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specifymore » the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented.« less

Impact of the Tilted Detector Solenoid on the Ion Polarization at JLEIC

DOE PAGES

Kondratenko, A. M.; Kondratenko, M. A.; Filatov, Yu N.; ...

2017-12-01

Jefferson Lab Electron Ion Collider (JLEIC) is a figure-8 collider "transparent" to the spin. This allows one to control the ion polarization using a universal 3D spin rotator based on weak solenoids. Besides the 3D spin rotator, a coherent effect on the spin is produced by a detector solenoid together with the dipole correctors and anti-solenoids compensating betatron oscillation coupling. The 4 m long detector solenoid is positioned along a straight section of the electron ring and makes a 50 mrad horizontal angle with a straight section of the ion ring. Such a large crossing angle is needed for amore » quick separation of the two colliding beams near the interaction point to make sufficient space for placement of interaction region magnets and to avoid parasitic collisions of shortly-spaced 476 MHz electron and ion bunches. We present a numerical analysis of the detector solenoid effect on the proton and deuteron polarizations. We demonstrate that the effect of the detector solenoid on the proton and deuteron polarizations can be compensated globally using an additional 3D rotator located anywhere in the ring.« less

Impact of the Tilted Detector Solenoid on the Ion Polarization at JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondratenko, A. M.; Kondratenko, M. A.; Filatov, Yu N.

Jefferson Lab Electron Ion Collider (JLEIC) is a figure-8 collider "transparent" to the spin. This allows one to control the ion polarization using a universal 3D spin rotator based on weak solenoids. Besides the 3D spin rotator, a coherent effect on the spin is produced by a detector solenoid together with the dipole correctors and anti-solenoids compensating betatron oscillation coupling. The 4 m long detector solenoid is positioned along a straight section of the electron ring and makes a 50 mrad horizontal angle with a straight section of the ion ring. Such a large crossing angle is needed for amore » quick separation of the two colliding beams near the interaction point to make sufficient space for placement of interaction region magnets and to avoid parasitic collisions of shortly-spaced 476 MHz electron and ion bunches. We present a numerical analysis of the detector solenoid effect on the proton and deuteron polarizations. We demonstrate that the effect of the detector solenoid on the proton and deuteron polarizations can be compensated globally using an additional 3D rotator located anywhere in the ring.« less

Crab cavities: Past, present, and future of a challenging device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Q.

2015-05-03

In two-ring facilities operating with a crossing-angle collision scheme, luminosity can be limited due to an incomplete overlapping of the colliding bunches. Crab cavities then are introduced to restore head-on collisions by providing the destined opposite deflection to the head and tail of the bunch. An increase in luminosity was demonstrated at KEKB with global crab-crossing, while the Large Hardron Collider (LHC) at CERN currently is designing local crab crossing for the Hi-Lumi upgrade. Future colliders may investigate both approaches. In this paper, we review the challenges in the technology, and the implementation of crab cavities, while discussing experience inmore » earlier colliders, ongoing R&D, and proposed implementations for future facilities, such as HiLumi-LHC, CERN’s compact linear collider (CLIC), the international linear collider (ILC), and the electron-ion collider under design at BNL (eRHIC).« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Derbenev, Yaroslav S.; Morozov, Vasiliy; Lin, Fanglei

We present a complete scheme for managing the polarization of ion beams in Jefferson Lab's proposed Medium-energy Electron-Ion Collider (MEIC). It provides preservation of the ion polarization during all stages of beam acceleration and polarization control in the collider's experimental straights. We discuss characteristic features of the spin motion in accelerators with Siberian snakes and in accelerators of figure-8 shape. We propose 3D spin rotators for polarization control in the MEIC ion collider ring. We provide polarization calculations in the collider with the 3D rotator for deuteron and proton beams. The main polarization control features of the figure-8 design aremore » summarized.« less

Longitudinal space charge compensation at PSR

NASA Astrophysics Data System (ADS)

Neri, Filippo

1998-11-01

The longitudinal space-charge force in neutron spallation source compressor ring or other high intensity proton storage rings can be compensated by introducing an insert in the ring. The effect of the inductor is to cancel all or part of the space charge potential, because it is capacitive. The Proton Storage Ring at Los Alamos National Laboratory is a compressor ring used to produce short pulses of spallation neutrons. Inductive inserts design for space charge compensation at the Los Alamos Proton Storage Ring is described.

Dynamics of planetary rings

NASA Technical Reports Server (NTRS)

Araki, Suguru

1991-01-01

The modeling of the dynamics of particle collisions within planetary rings is discussed. Particles in the rings collide with one another because they have small random motions in addition to their orbital velocity. The orbital speed is roughly 10 km/s, while the random motions have an average speed of about a tenth of a millimeter per second. As a result, the particle collisions are very gentle. Numerical analysis and simulation of the ring dynamics, performed with the aid of a supercomputer, is outlined.

Development of muon ring coolers, neutrino factories and supersymmetric Higgs factory

NASA Astrophysics Data System (ADS)

Cline, David B.

2003-08-01

Over the past few years or so a key new development is the invention of ring coolers for muon cooling. In particular, these rings demonstrate robust cooling of the longitudinal phase space. We discuss the quadrupole or UCLA ring cooler and the prospects to make this a final cooler to reduce the transceiver emittance to the value required for a mu+mu- collider. This will lead to a Higgs factory for the A0/H0 in supersymmetry models.

Development of Muon Ring Coolers, Neutrino Factories and Supersymmetric Higgs Factory

NASA Astrophysics Data System (ADS)

Cline, David B.

2002-12-01

Over the past few years or so a key new development is the invention of Ring Coolers for muon cooling. In particular these rings demonstrate robust cooling of the longitudinal phase space. We discuss the Quadrupole or UCLA Ring Cooler and the prospects to make this a final cooler to reduce the tranceiver emittance to the value required for a μ+ μ- collider. This will lead to a Higgs Factory for the A0/H0 in supersymmetry models.

Experimental Observation of Fermi-Pasta-Ulam Recurrence in a Nonlinear Feedback Ring System

NASA Astrophysics Data System (ADS)

Wu, Mingzhong; Patton, Carl E.

2007-01-01

Fermi-Pasta-Ulam recurrence through soliton dynamics has been realized. The experiment used a magnetic film strip-based active feedback ring. At some ring gain level, a wide spin wave pulse is self-generated in the ring. As the pulse circulates, it separates into two envelop solitons with different speeds. When the fast soliton catches up and collides with the slow soliton, the initial wide pulse is perfectly reconstructed. The repetition of this process leads to periodic recurrences of the initial pulse.

A Superstrong Adjustable Permanent Magnet for the Final Focus Quadrupole in a Linear Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihara, T.

A super strong permanent magnet quadrupole (PMQ) was fabricated and tested. It has an integrated strength of 28.5T with overall length of 10 cm and a 7mm bore radius. The final focus quadrupole of a linear collider needs a variable focal length. This can be obtained by slicing the magnet into pieces along the beamline direction and rotating these slices. But this technique may lead to movement of the magnetic center and introduction of a skew quadrupole component when the strength is varied. A ''double ring structure'' can ease these effects. A second prototype PMQ, containing thermal compensation materials andmore » with a double ring structure, has been fabricated. Worm gear is selected as the mechanical rotating scheme because the double ring structure needs a large torque to rotate magnets. The structure of the second prototype PMQ is shown.« less

Simulation of radiation damping in rings, using stepwise ray-tracing methods

DOE PAGES

Meot, F.

2015-06-26

The ray-tracing code Zgoubi computes particle trajectories in arbitrary magnetic and/or electric field maps or analytical field models. It includes a built-in fitting procedure, spin tracking many Monte Carlo processes. The accuracy of the integration method makes it an efficient tool for multi-turn tracking in periodic machines. Energy loss by synchrotron radiation, based on Monte Carlo techniques, had been introduced in Zgoubi in the early 2000s for studies regarding the linear collider beam delivery system. However, only recently has this Monte Carlo tool been used for systematic beam dynamics and spin diffusion studies in rings, including eRHIC electron-ion collider projectmore » at the Brookhaven National Laboratory. Some beam dynamics aspects of this recent use of Zgoubi capabilities, including considerations of accuracy as well as further benchmarking in the presence of synchrotron radiation in rings, are reported here.« less

Total water storage dynamics derived from tree-ring records and terrestrial gravity observations

NASA Astrophysics Data System (ADS)

Creutzfeldt, Benjamin; Heinrich, Ingo; Merz, Bruno

2015-10-01

For both societal and ecological reasons, it is important to understand past and future subsurface water dynamics but estimating subsurface water storage is notoriously difficult. In this pilot study, we suggest the reconstruction of subsurface water dynamics by a multi-disciplinary approach combining hydrology, dendrochronology and geodesy. In a first step, nine complete years of high-precision gravimeter observations are used to estimate water storage changes in the subsurface at the Geodetic Observatory Wettzell in the Bavarian Forest, Germany. The record is extended to 63 years by calibrating a hydrological model against the 9 years of gravimeter observations. The relationship between tree-ring growth and water storage changes is evaluated as well as that between tree-ring growth and supplementary hydro-meteorological data. Results suggest that tree-ring growth is influenced primarily by subsurface water storage. Other variables related to the overall moisture status (e.g., Standardized Precipitation Index, Palmer Drought Severity Index, streamflow) are also strongly correlated with tree-ring width. While these indices are all indicators of water stored in the landscape, water storage changes of the subsurface estimated by depth-integral measurements give us the unique opportunity to directly reconstruct subsurface water storage dynamics from records of tree-ring width. Such long reconstructions will improve our knowledge of past water storage variations and our ability to predict future developments. Finally, knowing the relationship between subsurface storage dynamics and tree-ring growth improves the understanding of the different signal components contained in tree-ring chronologies.

Observation of electron cloud instabilities and emittance dilution at the Cornell electron-positron Storage ring Test Accelerator

DOE PAGES

Holtzapple, R. L.; Billing, M. G.; Campbell, R. C.; ...

2016-04-11

Electron cloud related emittance dilution and instabilities of bunch trains limit the performance of high intensity circular colliders. One of the key goals of the Cornell electron-positron storage ring Test Accelerator (CesrTA) research program is to improve our understanding of how the electron cloud alters the dynamics of bunches within the train. Single bunch beam diagnostics have been developed to measure the beam spectra, vertical beam size, two important dynamical effects of beams interacting with the electron cloud, for bunch trains on a turn-by-turn basis. Experiments have been performed at CesrTA to probe the interaction of the electron cloud withmore » stored positron bunch trains. The purpose of these experiments was to characterize the dependence of beam-electron cloud interactions on the machine parameters such as bunch spacing, vertical chromaticity, and bunch current. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 1) a gated beam position monitor (BPM) and spectrum analyzer to measure the bunch-by-bunch frequency spectrum of the bunch trains, 2) an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this study we report on the observations from these experiments and analyze the effects of the electron cloud on the stability of bunches in a train under many different operational conditions.« less

Observation of Electron Cloud Instabilities and Emittance Dilution at the Cornell Electron-Positron Storage Ring Test Accelerator

NASA Astrophysics Data System (ADS)

Holtzapple, R. L.; Billing, M. G.; Campbell, R. C.; Dugan, G. F.; Flanagan, J.; McArdle, K. E.; Miller, M. I.; Palmer, M. A.; Ramirez, G. A.; Sonnad, K. G.; Totten, M. M.; Tucker, S. L.; Williams, H. A.

2016-04-01

Electron cloud related emittance dilution and instabilities of bunch trains limit the performance of high intensity circular colliders. One of the key goals of the Cornell electron-positron storage ring Test Accelerator (CesrTA) research program is to improve our understanding of how the electron cloud alters the dynamics of bunches within the train. Single bunch beam diagnotics have been developed to measure the beam spectra, vertical beam size, two important dynamical effects of beams interacting with the electron cloud, for bunch trains on a turn-by-turn basis. Experiments have been performed at CesrTA to probe the interaction of the electron cloud with stored positron bunch trains. The purpose of these experiments was to characterize the dependence of beam-electron cloud interactions on the machine parameters such as bunch spacing, vertical chromaticity, and bunch current. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 1) a gated beam position monitor (BPM) and spectrum analyzer to measure the bunch-by-bunch frequency spectrum of the bunch trains; 2) an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the observations from these experiments and analyze the effects of the electron cloud on the stability of bunches in a train under many different operational conditions.

Studies of electron cooling at DESY

NASA Astrophysics Data System (ADS)

Balewski, K.; Brinkmann, R.; Derbenev, Y.; Floettmann, K.; Wesolowski, P.; Gentner, M.; Husmann, D.; Steier, C.

2000-02-01

A possibility to improve the luminosity in hadron colliders is to apply electron cooling. For the e-p and possibly in the future for e-ion a cooling scheme is proposed for the HERA collider which improves the brightness of the hadron beam in two steps. In a first step the hadron beam is cooled at an energy of 15-20 GeV in the pre-accelerator PETRA. In a second step the hadrons are cooled at top energy in HERA, mainly to maintain the beam quality. The first part of the cooler in PETRA consists of a thermionic gun which delivers electron bunches of 120 keV. These bunches are then compressed so that they fit into a 208 MHz travelling wave linac where they are accelerated to an energy of 10 MeV. Gun, compressor, and linac are surrounded by a solenoid so that emittance growth is avoided especially at the low energy end. In order to reduce the energy spread of the electron beam and to lengthen it, the electrons run through a decompressor before they are brought together with the hadron beam in a 40 m long cooling section which is again surrounded by a solenoid. In this paper a schematic layout of the system will be presented and simulation results of the first part of the cooler will be shown. The cooler in HERA consists of a small electron storage ring with two long straight sections. It is shown that all requirements of such a ring running at an energy between 180 and 450 MeV can be met to fight emittance growth in case of light hadron beams (protons) and to cool heavy ions sufficiently fast.

Experimental Studies on the Collision Behavior of Saturnian Ice Particles

NASA Astrophysics Data System (ADS)

Heißelmann, D.; Fraser, H. J.; Blum, J.

2008-09-01

The processes in the Saturnian rings are dominated by two effects. On the one hand there is a gravitational interaction of the ring particles with Saturn or its moons and moonlets increasing the eccentricity of the rings. On the other hand inelastic collisions between the ring particles occur and result in damping of the particles' motion and therefore circularizing the orbits and locally confining the rings [1]. As spectroscopic measurements of the Saturnian rings have shown, the ring particles consist of almost pure water ice (with little amounts of organic materials and carbon) [2]. The determination of the size distribution of the ring constituents from Cassini and Voyager data revealed typical particles sizes between 1 cm and 10m. In contrast to the numerous observational data obtained by spaceborne and ground-based methods only very little experimental data exist on the collision properties of icy particles. Up to now laboratory measurements were only performed for quasi-two-dimensional, central collisions of large icy spheres [3, 4, 5]. We will present results from parabolic flight experiments in which pairs of ice particles of spherical and irregular shape were collided in a microgravity environment. The projectiles with sizes of 3mm to 15mm were accelerated to velocities between 3 cm s-1 and 20 cm s-1 and gently collided inside a cryogenic high-vacuum chamber. The impacts were recorded by a high-speed, high-resolution digital imaging system which was equipped with a beamsplitter optics to obtain three-dimensional information about the impact parameters and the coefficients of restitution (the ratio of velocity after and before the collision). Additionally we will report on microgravity studies investigating collisions of an ensemble of one hundred cmsized spheres. The prototype experiments were conducted with solid glass beads with a rough surface colliding at relative velocities of 0.5 cm s-1 to 10 cm s-1. We will compare the results to the collisions of pairs of icy bodies and will report on future laboratory studies of similar experiments with rubber beads and ice particles.

Next generation HOM-damping

NASA Astrophysics Data System (ADS)

Marhauser, Frank

2017-06-01

Research and development for superconducting radio-frequency cavities has made enormous progress over the last decades from the understanding of theoretical limitations to the industrial mass fabrication of cavities for large-scale particle accelerators. Key technologies remain hot topics due to continuously growing demands on cavity performance, particularly when in pursuit of high quality beams at higher beam currents or higher luminosities than currently achievable. This relates to higher order mode (HOM) damping requirements. Meeting the desired beam properties implies avoiding coupled multi-bunch or beam break-up instabilities depending on the machine and beam parameters that will set the acceptable cavity impedance thresholds. The use of cavity HOM-dampers is crucial to absorb the wakefields, comprised by all beam-induced cavity Eigenmodes, to beam-dynamically safe levels and to reduce the heat load at cryogenic temperature. Cavity damping concepts may vary, but are principally based on coaxial and waveguide couplers as well as beam line absorbers or any combination. Next generation energy recovery linacs and circular colliders call for cavities with strong HOM-damping that can exceed the state-of-the-art, while the operating mode efficiency shall not be significantly compromised concurrently. This imposes major challenges given the rather limited damping concepts. A detailed survey of established cavities is provided scrutinizing the achieved damping performance, shortcomings, and potential improvements. The scaling of the highest passband mode impedances is numerically evaluated in dependence on the number of cells for a single-cell up to a nine-cell cavity, which reveals the increased probability of trapped modes. This is followed by simulations for single-cell and five-cell cavities, which incorporate multiple damping schemes to assess the most efficient concepts. The usage and viability of on-cell dampers is elucidated for the single-cell cavity since it can push the envelope towards quasi HOM-free operation suited for next generation storage and collider rings. Geometrical end-cell shape alterations for the five-cell cavity with already efficient mode damping are discussed as a possibility to further lower specific high impedance modes. The findings are eventually put into relation with demanding impedance instability thresholds in future collider rings.

Next generation HOM-damping

DOE PAGES

Marhauser, Frank

2017-05-15

Research and development for superconducting radio-frequency cavities has made enormous progress over the last decades from the understanding of theoretical limitations to the industrial mass fabrication of cavities for large-scale particle accelerators. Key technologies remain hot topics due to continuously growing demands on cavity performance, particularly when in pursuit of high quality beams at higher beam currents or higher luminosities than currently achievable. This relates to Higher Order Mode (HOM) damping requirements. Meeting the desired beam properties implies avoiding coupled multi-bunch or beam break-up instabilities depending on the machine and beam parameters that will set the acceptable cavity impedance thresholds.more » The use of cavity HOM-dampers is crucial to absorb the wakefields, comprised by all beam-induced cavity Eigenmodes, to beam-dynamically safe levels and to reduce the heat load at cryogenic temperature. Cavity damping concepts may vary, but are principally based on coaxial and waveguide couplers as well as beam line absorbers or any combination. Next generation Energy Recovery Linacs and circular colliders call for cavities with strong HOM-damping that can exceed the state-of-the-art, while the operating mode efficiency shall not be significantly compromised concurrently. This imposes major challenges given the rather limited damping concepts. A detailed survey of established cavities is provided scrutinizing the achieved damping performance, shortcomings, and potential improvements. The scaling of the highest passband mode impedances is numerically evaluated in dependence on the number of cells for a single-cell up to a nine-cell cavity, which reveals the increased probability of trapped modes. This is followed by simulations for single-cell and five-cell cavities, which incorporate multiple damping schemes to assess the most efficient concepts. The usage and viability of on-cell dampers is elucidated for the single-cell cavity since it can push the envelope towards quasi HOM-free operation suited for next generation storage and collider rings. Geometrical end-cell shape alterations for the five-cell cavity with already efficient mode damping are discussed as a possibility to further lower specific high impedance modes. Lastly, the findings are eventually put into relation with demanding impedance instability thresholds in future collider rings.« less

Antiproton acceleration in the Fermilab Main Ring and Tevatron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, P.; Dinkel, J.; Ducar, R.

1987-03-01

The operation of the Fermilab Main Ring and Tevatron rf systems for colliding beams physics is discussed. The changes in the rf feedback system required for the accelration of antiprotons, and the methods for achieving proper transfer of both protons and antiprotons are described. Data on acceleration and transfer efficiencies are presented.

Beam dynamics and expected performance of Sweden's new storage-ring light source: MAX IV

NASA Astrophysics Data System (ADS)

Leemann, S. C.; Andersson, Å.; Eriksson, M.; Lindgren, L.-J.; Wallén, E.; Bengtsson, J.; Streun, A.

2009-12-01

MAX IV will be Sweden’s next-generation high-performance synchrotron radiation source. The project has recently been granted funding and construction is scheduled to begin in 2010. User operation for a broad and international user community should commence in 2015. The facility is comprised of two storage rings optimized for different wavelength ranges, a linac-based short-pulse facility and a free-electron laser for the production of coherent radiation. The main radiation source of MAX IV will be a 528 m ultralow emittance storage ring operated at 3 GeV for the generation of high-brightness hard x rays. This storage ring was designed to meet the requirements of state-of-the-art insertion devices which will be installed in nineteen 5 m long dispersion-free straight sections. The storage ring is based on a novel multibend achromat design delivering an unprecedented horizontal bare lattice emittance of 0.33 nm rad and a vertical emittance below the 8 pm rad diffraction limit for 1 Å radiation. In this paper we present the beam dynamics considerations behind this storage-ring design and detail its expected unique performance.

Dynamics of collision of a vortex ring and a planar surface

NASA Astrophysics Data System (ADS)

McErlean, Michael; Krane, Michael; Fontaine, Arnold

2008-11-01

The dynamics of the impact between a vortex ring and a planar surface is presented. The vortex rings, generated by piston injection of a slug of water into a quiescent water tank, collide with a surface oriented normally to the ring's direction of travel. The time evolution of both the force imparted to a planar surface and the wall pressure are presented. These are supplemented by DPIV measurements of the evolution of ring strength and structure, before and during impact. The relation between changes in ring structure during collision and the waveforms of impact force and wall pressure will be discussed.

Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

NASA Astrophysics Data System (ADS)

Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

2012-04-01

Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily controlled by total water storage in the subsurface. But high uncertainties intervals of the correlation coefficient urges for the extension of the measurement period. This multi-disciplinary study, combining hydrology, dendrochronology and geodesy shows that temporal gravimeter measurements may give us the unique opportunity to retrieve the information of total water storage contained in tree-ring records to reconstruct total water storage dynamics. Knowing the relationship of water storage and tree-ring growth can also support the reconstruction of other climate records based on tree-ring series, help with hydrological model testing and can improve our knowledge of long-term variations of water storage in the past.

Status of DAFNE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Preger, M.; /Frascati; Alesini, D.

DA{Phi}NE is a double ring electron-positron collider, designed to provide very high luminosity at the energy of the {Phi} resonance (1.02 GeV c.m.). After storing the first beam in fall 1997, the collider was commissioned without solenoidal detectors until the end of 1998, reaching a single bunch luminosity of 1.6 x 10{sup 30} cm{sup -2}s{sup -1} with 20 mA in each beam, corresponding to a beam-beam tune shift of {approx} 0.03. A longitudinal bunch-to-bunch feedback has been implemented, allowing the storage of more than 0.5 A in 30 bunches for both electrons and positrons. The KLOE detector, embedded into amore » superconducting solenoid with strong longitudinal field integral (2.4 Tm, to be compared to a magnetic rigidity of 1.7 Tm) compensated by two other solenoids of opposite field, was installed in winter 1999 and commissioning resumed with a careful correction of the coupling effects. Particular effort has been dedicated to the reduction of background in the experiment, which led to the possibility of injecting the beams in interaction without switching off data taking. The total stored current has reached more than 1 A in each beam, while a transverse feedback system has been realized to counteract vertical instabilities occurring during injection. The collider is now running in the multibunch mode for KLOE data taking with peak luminosity up to 1.8 x 10{sup 31} cm{sup -2}s{sup -1} and integrated luminosity larger than 0.8 pb{sup -1} per day.« less

A Study on Double Event Detection for PHENIX at RHIC

NASA Astrophysics Data System (ADS)

Vazquez-Carson, Sebastian; Phenix Collaboration

2016-09-01

Many measurements made in Heavy Ion experiments such as PHENIX at RHIC focus on geometrical properties because phenomena such as collective flow give insight into quark-gluon plasma and the strong nuclear force. As part of this investigation, PHENIX has taken data in 2016 for deuteron on gold collisions at several energies. An acceptable luminosity is achieved by injecting up to 120 separate bunches each with billions of ions into the storage ring, from which two, separate beams are made to collide. This method has a drawback as there is a chance for multiple pairs of nuclei to collide in a single bunch crossing. Data taken in a double event cannot be separated into two independent events and has no clear interpretation. This effect's magnitude is estimated and incorporated in published results as a systematic uncertainty and studies on this topic have already been conducted within PHENIX. I develop several additional algorithms to flag multiple interaction events by examining the time dependence of data from the two Beam-Beam Counters - detectors surrounding the beam pipe on opposite ends of the interaction region. The algorithms are tested with data, in which events with double interactions are artificially produced using low luminosity data. I am working at the University of Colorado at Boulder on behalf of the PHENIX collaboration.

Planning and Prototyping for a Storage Ring Measurement of the Proton Electric Dipole Moment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talman, Richard

2015-07-01

Electron and proton EDM's can be measured in "frozen spin" (with the beam polarization always parallel to the orbit, for example) storage rings. For electrons the "magic" kinetic energy at which the beam can be frozen is 14.5 MeV. For protons the magic kinetic energy is 230 MeV. The currently measured upper limit for the electron EDM is much smaller than the proton EDM upper limit, which is very poorly known. Nevertheless, because the storage ring will be an order of magnitude cheaper, a sensible plan is to first build an all-electric electron storage ring as a prototype. Such anmore » electron ring was successfully built at Brookhaven, in 1954, as a prototype for their AGS ring. This leaves little uncertainty concerning the cost and performance of such a ring. (This is documentedin one of the Physical Review papers mentioned above.)« less

Storage-ring Electron Cooler for Relativistic Ion Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Fanglei; Derbenev, Yaroslav; Douglas, David R.

Application of electron cooling at ion energies above a few GeV has been limited due to reduction of electron cooling efficiency with energy and difficulty in producing and accelerating a high-current high-quality electron beam. A high-current storage-ring electron cooler offers a solution to both of these problems by maintaining high cooling beam quality through naturally-occurring synchrotron radiation damping of the electron beam. However, the range of ion energies where storage-ring electron cooling can be used has been limited by low electron beam damping rates at low ion energies and high equilibrium electron energy spread at high ion energies. This papermore » reports a development of a storage ring based cooler consisting of two sections with significantly different energies: the cooling and damping sections. The electron energy and other parameters in the cooling section are adjusted for optimum cooling of a stored ion beam. The beam parameters in the damping section are adjusted for optimum damping of the electron beam. The necessary energy difference is provided by an energy recovering SRF structure. A prototype linear optics of such storage-ring cooler is presented.« less

Physics issues in diffraction limited storage ring design

NASA Astrophysics Data System (ADS)

Fan, Wei; Bai, ZhengHe; Gao, WeiWei; Feng, GuangYao; Li, WeiMin; Wang, Lin; He, DuoHui

2012-05-01

Diffraction limited electron storage ring is considered a promising candidate for future light sources, whose main characteristics are higher brilliance, better transverse coherence and better stability. The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance. Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design. As an example of application, partial physical design of HALS (Hefei Advanced Light Source), which is a diffraction limited VUV and soft X-ray light source, was introduced. Severe emittance growth due to the Intra Beam Scattering effect, which is the main obstacle to achieve ultra low emittance, was estimated quantitatively and possible cures were discussed. It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.

CLEARING MAGNET DESIGN FOR APS-U

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abliz, M.; Grimmer, J.; Jaski, Y.

2017-06-25

The Advanced Photon Source is in the process of developing an upgrade (APS-U) of the storage ring. The upgrade will be converting the current double bend achromat (DBA) lattice to a multi-bend achromat (MBA) lattice. In addition, the storage ring will be operated at 6 GeV and 200 mA with regular swap-out injection to keep the stored beam current constant [1]. The swap-out injection will take place with beamline shutters open. For radiation safety to ensure that no electrons can exit the storage ring, a passive method of protecting the beamline and containing the electrons inside the storage ring ismore » proposed. A clearing magnet will be located in all beamline front ends inside the storage ring tunnel. This article will discuss the features and design of the clearing magnet scheme for APS-U.« less

National Synchrotron Light Source II storage ring vacuum systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hseuh, Hsiao-Chaun, E-mail: hseuh@bnl.gov; Hetzel, Charles; Leng, Shuwei

2016-05-15

The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. The majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. This paper presents themore » design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

The phase slip factor of the electrostatic cryogenic storage ring CSR

NASA Astrophysics Data System (ADS)

Grieser, Manfred; von Hahn, Robert; Vogel, Stephen; Wolf, Andreas

2017-07-01

To determine the momentum spread of an ion beam from the measured revolution frequency distribution, the knowledge of the phase slip factor of the storage ring is necessary. The slip factor was measured for various working points of the cryogenic storage ring CSR at MPI for Nuclear Physics, Heidelberg and was compared with simulations. The predicted functional relationship of the slip factor and the horizontal tune depends on the different islands of stability, which has been experimentally verified. This behavior of the slip factor is in clear contrast to that of magnetic storage rings.

Online optimization of storage ring nonlinear beam dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Xiaobiao; Safranek, James

2015-08-01

We propose to optimize the nonlinear beam dynamics of existing and future storage rings with direct online optimization techniques. This approach may have crucial importance for the implementation of diffraction limited storage rings. In this paper considerations and algorithms for the online optimization approach are discussed. We have applied this approach to experimentally improve the dynamic aperture of the SPEAR3 storage ring with the robust conjugate direction search method and the particle swarm optimization method. The dynamic aperture was improved by more than 5 mm within a short period of time. Experimental setup and results are presented.

Dynamics of collision of a vortex ring and a planar surface

NASA Astrophysics Data System (ADS)

McErlean, Michael; Krane, Michael; Fontaine, Arnold

2009-11-01

The dynamics of the impact between a vortex ring and a planar surface orientated perpendicular to the direction of travel are presented. High Reynolds number vortex rings are injected into a quiescent tank of water using a piston-cylinder generator before colliding with a target at a long distance. Both the pressure at the stagnation point on the surface and the force imparted to the target by the ring impact are measured directly. The changes in both are related to the ring motion and deformation captured by high speed digital video, and DPIV measurements. These relations are used to develop a scaling law relation between impact force and vortex ring circulation, speed, and size.

Physical studies of the planetary rings

NASA Technical Reports Server (NTRS)

Ip, W.-H.

1980-01-01

In this review paper, the physical properties of the Saturnian and Uranian rings as derived from ground-based observations are first discussed. Focus is then shifted to the study of the orbital dynamics of the ring particles. Numerical simulations of the evolutionary history of a system of colliding particles in differential rotation together with theoretical modeling of the inelastic collision processes are surveyed. In anticipation of the information returned from in situ measurements by space probes, interactions of the planetary rings with the interplanetary meteoroids and planetary magnetospheres are briefly considered. Finally, models of planetary ring origin are examined. In this connection, some recent work on the satellite resonant perturbation effects on the ring structure are also touched upon.

SSC [Superconducting Super Collider] Project: Technical Training for the Future of Texas. Navarro College/Dallas Community College District. Final Report for Year One.

ERIC Educational Resources Information Center

Orsak, Charles; McGlohen, Patti J.

The Superconducting Super Collider Laboratory (SSCL) is a national lab for research on the fundamental forces and constituents of the universe. A major part of the research will involve an oval ring 54 miles in circumference through which superconducting magnets will steer two beams of protons in opposite directions. In response to the…

Large diameter metal ring seal prevents gas leakage at 5000 psi

NASA Technical Reports Server (NTRS)

Middelkoop, J. H.

1966-01-01

Large metal ring seal prevents gas leakage in hydrogen, helium, or nitrogen storage bottles at pressures up to 5,000 psi. The grooved ring seal which contains elastomer O-rings is installed between the mating faces of the access cover and the storage bottle.

Storage Rings for Science with: Electron-Positron Collisions, Hadron Collisions and Synchrotron Light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozaki,S.

2009-05-04

The author is honored to receive the 2009 Robert Wilson Prize and the recognition that comes with it. The citation for the prize reads, 'For his outstanding contribution to the design and construction of accelerators that has led to the realization of major machines for fundamental science on two continents and his promotion of international collaboration.' In this article, he will discuss the two construction projects, which he led, one (TRISTAN e{sup +}e{sup -} Collider at KEK) in Japan and the other (RHIC at BNL) in the USA, covering project issues and lessons learned from these projects. Although both ofmore » them were built on separate continents, it is interesting to note that they are both built on long off-shore islands. He will also add comments on his recent engagement in the development of the Conceptual Design for the National Synchrotron Light Source II (NSLS-II).« less

Nuclear stopping and collective flow in CSR/LanZhou energy region

NASA Astrophysics Data System (ADS)

Luo, X.-F.; Dong, X.; Shao, M.; Li, C.; Chen, H.-F.; Wu, K.-J.; Xu, H.-S.

2011-06-01

Nuclear stopping and collective flow for two pairs of symmetric colliding nuclei: 238U+238U and 129Xe+129Xe, which are proposed to be accelerated on Cooling Storage Ring (CSR), External Target Facility (ETF), LanZhou, China, are studied by a hadronic transport model ART1.0. The incident beam energy of Uranium and Xenon can be delivered up to 520 MeV/nucleon and 900MeV/nucleon, respectively. At this CSR energy region, the hot, dense nuclear matter are thought to be obtained in the lab, which is an idea circumstance to study the nuclear equation of state (EoS). As deformation of the Uranium nuclei, it is predicted that significant large baryon density in the tip-tip U+U collision patterns and the large elliptic flow in body-body collision pattern are both avail to study the nuclear EoS.

The influence of train leakage currents on the LEP dipole field

NASA Astrophysics Data System (ADS)

Bravin, E.; Brun, G.; Dehning, B.; Drees, A.; Galbraith, P.; Geitz, M.; Henrichsen, K.; Koratzinos, M.; Mugnai, G.; Tonutti, M.

The determination of the mass and the width of the Z boson at CERN's LEP accelerator, an e+e- storage ring with a circumference of approximately 27 km, imposes heavy demands on the knowledge of the LEP counter-rotating electron and positron beam energies. The precision required is of the order of 1 MeV or ≈ 20 ppm. Due to its size, the LEP collider is influenced by various macroscopic and regional factors such as the position of the moon or seasonal changes of the rainfall in the area, as reported earlier. A new and not less surprising effect on the LEP energy was observed in 1995: railroad trains in the Geneva region perturb the dipole field. A parasitic flow of electricity, originating from the trains, travels along the LEP vacuum chamber, affecting the LEP dipole field. An account of the phenomenon with its explanation substantiated by dedicated measurements is presented.

National Synchrotron Light Source II storage ring vacuum systems

DOE PAGES

Hseuh, Hsiao-Chaun; Hetzel, Charles; Leng, Shuwei; ...

2016-04-05

The National Synchrotron Light Source II, completed in 2014, is a 3-GeV synchrotron radiation (SR) facility at Brookhaven National Laboratory and has been in steady operation since. With a design electron current of 500 mA and subnanometer radians horizontal emittance, this 792-m circumference storage ring is providing the highest flux and brightness x-ray beam for SR users. Also, the majority of the storage ring vacuum chambers are made of extruded aluminium. Chamber sections are interconnected using low-impedance radiofrequency shielded bellows. SR from the bending magnets is intercepted by water-cooled compact photon absorbers resided in the storage ring chambers. Finally, thismore » paper presents the design of the storage ring vacuum system, the fabrication of vacuum chambers and other hardware, the installation, the commissioning, and the continuing beam conditioning of the vacuum systems.« less

Duke storage rink UV/VUV FEL: Status and prospects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Litvinenko, V.N.; Burnham, B.; Madey, J.M.J.

1995-12-31

The 1 GeV Duke storage ring was successfully commissioned with parameters exceeding initial specification. The OK-4 FEL has arrived at the Duke FEL laboratory from the Novosibirsk Institute of Nuclear Physics. The OK-4 installation and commissioning is in progress. In this paper we describe the up-to-date status of the Duke storage ring and the OK-4 FEL. The projected performance of the OK-4 UV/VUV FEL is presented based on the electron beam parameters achieved. Initial plans to operate the OK-4 UV/VUV FEL at the Duke 1 GeV storage ring are outlined. Future plans and prospects of both the OK-4 FEL andmore » the Duke storage ring are discussed.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richter, B.

In this paper I have reviewed the possibilities for new colliders that might be available in the 1990's. One or more new proton should be available in the late-90s based on plans of Europe, the US and the USSR. The two very high energy machines, LHC and SSC, are quite expensive, and their construction will be more decided by the politicians' view on the availability of resources than by the physicists' view of the need for new machines. Certainly something will be built, but the question is when. New electron colliders beyond LEP II could be available in the latemore » 1990's as well. Most of the people who have looked at this problem believe that at a minimum three years of RandD are required before a proposal can be made, two years will be required to convince the authorities to go ahead, and five years will be required to build such a machine. Thus the earliest time a new electron collider at high energy could be available is around 1988. A strong international RandD program will be required to meet that schedule. In the field of B factories, PSI's proposal is the first serious step beyond the capabilities of CESR. There are other promising techniques but these need more RandD. The least RandD would be required for the asymmetric storage ring systems, while the most would be required for high luminosity linear colliders. For the next decade, high energy physics will be doing its work at the high energy frontier with Tevatron I and II, UNK, SLC, LEP I and II, and HERA. The opportunities for science presented by experiments at these facilities are very great, and it is to be hoped that the pressure for funding to construct the next generation facilities will not badly affect the operating budgets of the ones we now have or which will soon be turning on. 9 refs., 12 figs., 6 tabs.« less

A new storage-ring light source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, Alex

2015-06-01

A recently proposed technique in storage ring accelerators is applied to provide potential high-power sources of photon radiation. The technique is based on the steady-state microbunching (SSMB) mechanism. As examples of this application, one may consider a high-power DUV photon source for research in atomic and molecular physics or a high-power EUV radiation source for industrial lithography. A less challenging proof-of-principle test to produce IR radiation using an existing storage ring is also considered.

Inertial energy storage device

DOEpatents

Knight, Jr., Charles E.; Kelly, James J.; Pollard, Roy E.

1978-01-01

The inertial energy storage device of the present invention comprises a composite ring formed of circumferentially wound resin-impregnated filament material, a flanged hollow metal hub concentrically disposed in the ring, and a plurality of discrete filament bandsets coupling the hub to the ring. Each bandset is formed of a pair of parallel bands affixed to the hub in a spaced apart relationship with the axis of rotation of the hub being disposed between the bands and with each band being in the configuration of a hoop extending about the ring along a chordal plane thereof. The bandsets are disposed in an angular relationship with one another so as to encircle the ring at spaced-apart circumferential locations while being disposed in an overlapping relationship on the flanges of the hub. The energy storage device of the present invention has the capability of substantial energy storage due to the relationship of the filament bands to the ring and the flanged hub.

R&D status of linear collider technology at KEK

NASA Astrophysics Data System (ADS)

Urakawa, Junji

1992-02-01

This paper gives an outline of the Japan Linear Collider (JLC) project, especially JLC-I. The status of the various R&D works is particularly presented for the following topics: (1) electron and positron sources, (2) S-band injector linacs, (3) damping rings, (4) high power klystrons and accelerating structures, (5) the final focus system. Finally, the status of the construction and design studies for the Accelerator Test Facility (ATF) is summarized.

Design of the transfer line from booster to storage ring at 3 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bayar, C., E-mail: cafer.bayar@cern.ch; Ciftci, A. K., E-mail: abbas.kenan.ciftci@cern.ch

The Synchrotron Booster Ring accelerates the e-beam up to 3 GeV and particles are transported from booster to storage ring by transfer line. In this study, two options are considered, the first one is a long booster which shares the same tunnel with storage ring and the second one is a compact booster. As a result, two transfer line are designed based on booster options. The optical design is constrained by the e-beam Twiss parameters entering and leaving the transfer line. Twiss parameters in the extraction point of booster are used for the entrance of transfer line and are matchedmore » in the exit of transfer line to the injection point of the storage ring.« less

An Inside Look: NSLS-II Storage Ring

ScienceCinema

Fries, Gregory

2018-06-12

Look inside the storage ring of the National Synchrotron Light Source II, under construction at Brookhaven Lab. Exactly 843 magnets now encircle the ring. Their job will be to steer, stabilize, and store electrons racing around at near light speed.

Assessment of neutron skyshine near unmodified Accumulator Debuncher storage rings under Mu2e operational conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cossairt, J.Donald; /Fermilab

2010-12-01

Preliminary plans for providing the proton beam needed by the proposed Mu2e experiment at Fermilab will require the transport of 8 GeV protons to the Accumulator/Debuncher where they be processed into an intensity and time structure useful for the experiment. The intensities involved are far greater that those encountered with antiprotons of the same kinetic energy in the same beam enclosures under Tevatron Collider operational conditions, the operating parameters for which the physical facilities of the Antiproton Source were designed. This note explores some important ramifications of the proposed operation for radiation safety and demonstrates the need for extensive modificationsmore » of significant portions of the shielding of the Accumulator Debuncher storage rings; notably that underneath the AP Service Buildings AP10, AP30, and AP50. While existing shielding is adequate for the current operating mode of the Accumulator/Debuncher as part of the Antiproton Source used in the Tevatron Collider program, without significant modifications of the shielding configuration in the Accumulator/Debuncher region and/or beam loss control systems far more effective than seen in most applications at Fermilab, the proposed operational mode for Mu2e is not viable for the following reasons: 1. Due to skyshine alone, under normal operational conditions large areas of the Fermilab site would be exposed to unacceptable levels of radiation where most of the Laboratory workforce and some members of the general public who regularly visit Fermilab would receive measurable doses annually, contrary to workforce, public, and DOE expectations concerning the As Low as Reasonably Achievable (ALARA) principle. 2. Under normal operational conditions, a sizeable region of the Fermilab site would also require fencing due to skyshine. The size of the areas involved would likely invite public inquiry about the significant and visible enlargement of Fermilab's posted radiological areas. 3. There would be aesthetics questions about the employment of so much new fencing on the Fermilab site. 4. The assumption of only 1.0% 'normal condition' beam losses over the three locations is regarded as being extremely optimistic. Thus, it is evident that it is necessary to pursue shielding improvements to support viable operation of the Mu2e experiment.« less

Diffraction-limited storage-ring vacuum technology

PubMed Central

Al-Dmour, Eshraq; Ahlback, Jonny; Einfeld, Dieter; Tavares, Pedro Fernandes; Grabski, Marek

2014-01-01

Some of the characteristics of recent ultralow-emittance storage-ring designs and possibly future diffraction-limited storage rings are a compact lattice combined with small magnet apertures. Such requirements present a challenge for the design and performance of the vacuum system. The vacuum system should provide the required vacuum pressure for machine operation and be able to handle the heat load from synchrotron radiation. Small magnet apertures result in the conductance of the chamber being low, and lumped pumps are ineffective. One way to provide the required vacuum level is by distributed pumping, which can be realised by the use of a non-evaporable getter (NEG) coating of the chamber walls. It may not be possible to use crotch absorbers to absorb the heat from the synchrotron radiation because an antechamber is difficult to realise with such a compact lattice. To solve this, the chamber walls can work as distributed absorbers if they are made of a material with good thermal conductivity, and distributed cooling is used at the location where the synchrotron radiation hits the wall. The vacuum system of the 3 GeV storage ring of MAX IV is used as an example of possible solutions for vacuum technologies for diffraction-limited storage rings. PMID:25177979

ONLINE MINIMIZATION OF VERTICAL BEAM SIZES AT APS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yipeng

In this paper, online minimization of vertical beam sizes along the APS (Advanced Photon Source) storage ring is presented. A genetic algorithm (GA) was developed and employed for the online optimization in the APS storage ring. A total of 59 families of skew quadrupole magnets were employed as knobs to adjust the coupling and the vertical dispersion in the APS storage ring. Starting from initially zero current skew quadrupoles, small vertical beam sizes along the APS storage ring were achieved in a short optimization time of one hour. The optimization results from this method are briefly compared with the onemore » from LOCO (Linear Optics from Closed Orbits) response matrix correction.« less

Pushing the MAX IV 3 GeV storage ring brightness and coherence towards the limit of its magnetic lattice

NASA Astrophysics Data System (ADS)

Leemann, S. C.; Wurtz, W. A.

2018-03-01

The MAX IV 3 GeV storage ring is presently being commissioned and crucial parameters such as machine functions, emittance, and stored current have either already been reached or are approaching their design specifications. Once the baseline performance has been achieved, a campaign will be launched to further improve the brightness and coherence of this storage ring for typical X-ray users. During recent years, several such improvements have been designed. Common to these approaches is that they attempt to improve the storage ring performance using existing hardware provided for the baseline design. Such improvements therefore present more short-term upgrades. In this paper, however, we investigate medium-term improvements assuming power supplies can be exchanged in an attempt to push the brightness and coherence of the storage ring to the limit of what can be achieved without exchanging the magnetic lattice itself. We outline optics requirements, the optics optimization process, and summarize achievable parameters and expected performance.

Cabling design of booster and storage ring construction progress of TPS

NASA Astrophysics Data System (ADS)

Wong, Y.-S.; Liu, K.-B.; Liu, C.-Y.; Wang, b.-S.

2017-06-01

The 2012 Taiwan Photon Source (TPS) cable construction project started after 10 months to complete the cable laying and installation of power supply. The circumference of the booster ring (BR) is 496.8 m, whereas that of the storage ring (SR) is 518.4 m. Beam current is set to 500 mA at 3.3 GeV. The paper on grounding systems discusses the design of the ground wire (< 0.2 Ω) with low impedance, power supply of the accelerator and cabling tray. The flow and size of the ground current are carefully evaluated to avoid grounded current from flowing everywhere, which causes interference problems. In the design of the TPS, special shielding will be established to isolate the effects of electromagnetic interference on the magnet and ground current. Booster ring dipoles are connected by a series of 54-magnet bending dipole; the cable size of its stranded wire measures 250 mm2, with a total length of 5000 m. Booster ring and storage ring quadrupoles have 150 magnets; the cable size of their stranded wire is 250 mm2, with a total length of 17000 m. Storage ring dipole consists of 48 magnets; the cable size of its stranded wire is 325 mm2, with a total length of 6000 m. This study discusses the power supply cabling design of the storage ring and booster ring construction progress of TPS. The sections of this paper are divided into discussions of the construction of the control and instrument area, cabling layout of booster ring and storage ring, as well as the installation and commission machine. This study also discusses the use of a high-impedance meter to determine the effect of cabling insulation and TPS power supply machine on energy transfer to ensure the use of safe and correct magnet.

Baseline scheme for polarization preservation and control in the MEIC ion complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Derbenev, Yaroslav S.; Lin, Fanglei; Morozov, Vasiliy

2015-09-01

The scheme for preservation and control of the ion polarization in the Medium-energy Electron-Ion Collider (MEIC) has been under active development in recent years. The figure-8 configuration of the ion rings provides a unique capability to control the polarization of any ion species including deuterons by means of "weak" solenoids rotating the particle spins by small angles. Insertion of "weak" solenoids into the magnetic lattices of the booster and collider rings solves the problem of polarization preservation during acceleration of the ion beam. Universal 3D spin rotators designed on the basis of "weak" solenoids allow one to obtain any polarizationmore » orientation at an interaction point of MEIC. This paper presents the baseline scheme for polarization preservation and control in the MEIC ion complex.« less

Fission and fusion scenarios for magnetic microswimmer clusters

PubMed Central

Guzmán-Lastra, Francisca; Kaiser, Andreas; Löwen, Hartmut

2016-01-01

Fission and fusion processes of particle clusters occur in many areas of physics and chemistry from subnuclear to astronomic length scales. Here we study fission and fusion of magnetic microswimmer clusters as governed by their hydrodynamic and dipolar interactions. Rich scenarios are found that depend crucially on whether the swimmer is a pusher or a puller. In particular a linear magnetic chain of pullers is stable while a pusher chain shows a cascade of fission (or disassembly) processes as the self-propulsion velocity is increased. Contrarily, magnetic ring clusters show fission for any type of swimmer. Moreover, we find a plethora of possible fusion (or assembly) scenarios if a single swimmer collides with a ringlike cluster and two rings spontaneously collide. Our predictions are obtained by computer simulations and verifiable in experiments on active colloidal Janus particles and magnetotactic bacteria. PMID:27874006

Coupling Correction and Beam Dynamics at Ultralow Vertical Emittance in the ALS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steier, Christoph; Robin, D.; Wolski, A.

2008-03-17

For synchrotron light sources and for damping rings of linear colliders it is important to be able to minimize the vertical emittance and to correct the spurious vertical dispersion. This allows one to maximize the brightness and/or the luminosity. A commonly used tool to measure the skew error distribution is the analysis of orbit response matrices using codes like LOCO. Using the new Matlab version of LOCO and 18 newly installed power supplies for individual skew quadrupoles at the ALS the emittance ratio could be reduced below 0.1% at 1.9 GeV yielding a vertical emittance of about 5 pm. Atmore » those very low emittances, additional effects like intra beam scattering become more important, potentially limiting the minimum emittance for machine like the damping rings of linear colliders.« less

Cryogenic studies for the proposed CERN large hadron electron collider (LHEC)

NASA Astrophysics Data System (ADS)

Haug, F.; LHeC Study Team, The

2012-06-01

The LHeC (Large Hadron electron Collider) is a proposed future colliding beam facility for lepton-nucleon scattering particle physics at CERN. A new 60 GeV electron accelerator will be added to the existing 27 km circumference 7 TeV LHC for collisions of electrons with protons and heavy ions. Two basic design options are being pursued. The first is a circular accelerator housed in the existing LHC tunnel which is referred to as the "Ring-Ring" version. Low field normal conducting magnets guide the particle beam while superconducting (SC) RF cavities cooled to 2 K are installed at two opposite locations at the LHC tunnel to accelerate the beams. For this version in addition a 10 GeV re-circulating SC injector will be installed. In total four refrigerators with cooling capacities between 1.2 kW and 3 kW @ 4.5 K are needed. The second option, referred to as the "Linac-Ring" version consists of a race-track re-circulating energyrecovery type machine with two 1 km long straight acceleration sections. The 944 high field 2 K SC cavities dissipate 30 kW at CW operation. Eight 10 kW @ 4.5 K refrigerators are proposed. The particle detector contains a combined SC solenoid and dipole forming the cold mass and an independent liquid argon calorimeter. Cooling is done with two individual small sized cryoplants; a 4.5 K helium, and a 87 K liquid nitrogen plant.

Radial scaling in inclusive jet production at hadron colliders

NASA Astrophysics Data System (ADS)

Taylor, Frank E.

2018-03-01

Inclusive jet production in p-p and p ¯ -p collisions shows many of the same kinematic systematics as observed in single-particle inclusive production at much lower energies. In an earlier study (1974) a phenomenology, called radial scaling, was developed for the single-particle inclusive cross sections that attempted to capture the essential underlying physics of pointlike parton scattering and the fragmentation of partons into hadrons suppressed by the kinematic boundary. The phenomenology was successful in emphasizing the underlying systematics of the inclusive particle productions. Here we demonstrate that inclusive jet production at the Large Hadron Collider (LHC) in high-energy p-p collisions and at the Tevatron in p ¯ -p inelastic scattering shows similar behavior. The ATLAS inclusive jet production plotted as a function of this scaling variable is studied for √s of 2.76, 7 and 13 TeV and is compared to p ¯ -p inclusive jet production at 1.96 TeV measured at the CDF and D0 at the Tevatron and p-Pb inclusive jet production at the LHC ATLAS at √sNN=5.02 TeV . Inclusive single-particle production at Fermi National Accelerator Laboratory fixed target and Intersecting Storage Rings energies are compared to inclusive J /ψ production at the LHC measured in ATLAS, CMS and LHCb. Striking common features of the data are discussed.

Colliders Come of Age in Europe: PETRA and LEP

NASA Astrophysics Data System (ADS)

Hofmann, Albert

2003-04-01

Based on the success with early electron positron rings a new generation of facilities was constructed, optimized in cost and performance. In Europe PETRA was built at DESY with many innovations: smooth vacuum chamber with small impedance, efficient multi-cell RF-cavities, an optics giving an emittance optimized for luminosity, few bunches in head-on collision, a mini-beta scheme, accurate energy calibration based on depolarization resonances. From 1978 to 1986 PETRA provided high luminosity with over 22 GeV beam energy for particle physics experiments. The next ring, LEP at CERN, was optimized for two beam energy ranges, 46 and 93 - 105 GeV for Z0 and W production and particle search. This resulted in a large circumference of 27 km and low field bending magnets which had widely spaced laminations filled with concrete. The RF-voltage was produced in Cu cavities being coupled to low loss storage cavities at the lower, and with a superconducting RF-system, exceeding 3.6 GV, at the higher energy. Superconducting low beta insertions helped to obtain a high luminosity which reached integrated values of over 2000 1/nb per day at high energy. Very important for LEP was a precise energy calibration using depolarizing resonaces and careful control of all relevant parameters. LEP operated with four experiments from 1989 to 2000.

Ring Imaging Cherenkov Detector Technologies for Particle Identification in the Electron-Ion Collider Experiments

NASA Astrophysics Data System (ADS)

He, X.

In the proposed Electron-Ion Collider (EIC) experiments, particle identification (PID) of the final state hadrons in the semi-inclusive deep inelastic scattering allows the measurement of flavor-dependent gluon and quark distributions inside nucleons and nuclei. The EIC PID consortium (eRD14 Collaboration) has been formed for identifying and developing PID detectors using Ring Imaging Cherenkov (RICH) techniques for the EIC experiments. A modular Ring Imaging Cherenkov (mRICH) detector has been designed for particle identification in the momentum coverage from 3 GeV/c to 10 GeV/c. The mRICH detector consists of an aerogel radiator block, a Fresnel lens, a mirror-wall and a photosensor plane. The first prototype of this detector was successfully tested at Fermi National Accelerator Laboratory in April 2016 for verifying the detector working principles. This talk will highlight the mRICH beam test results and their comparison with GEANT4-based detector simulations. An implementation of the mRICH detector concept in the Forward Angle sPHENIX spectrometer at BNL will also be mentioned in this talk.

Coupled beam motion in a storage ring with crab cavities

DOE PAGES

Huang, Xiaobiao

2016-02-16

We studied the coupled beam motion in a storage ring between the transverse and longitudinal directions introduced by crab cavities. Analytic form of the linear decoupling transformation is derived. Also, the equilibrium bunch distribution in an electron storage ring with a crab cavity is given, including contribution to the eigen-emittance induced by the crab cavity. Furthermore, application to the short pulse generation scheme using crab cavities [1] is considered.

A multiple-orbit time-of-flight mass spectrometer based on a low energy electrostatic storage ring

NASA Astrophysics Data System (ADS)

Sullivan, M. R.; Spanjers, T. L.; Thorn, P. A.; Reddish, T. J.; Hammond, P.

2012-11-01

The results are presented for an electrostatic storage ring, consisting of two hemispherical deflector analyzers (HDA) connected by two separate sets of cylindrical lenses, used as a time-of-flight mass spectrometer. Based on the results of charged particle simulations and formal matrix model, the Ion Storage Ring is capable of operating with multiple stable orbits, for both single and multiply charged ions simultaneously.

Development of hermetic electrical connectors for SSC spool pieces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kountanis, B.; Kalny, L.

1993-05-01

The Superconducting Super Collider ring is about 54 miles (87 km circumference) and primarily includes a series of magnets. Spool piece assemblies are interspaced in the ring at predetermined intervals to provide specific functions such as cryogenic interfaces, vacuum interface, magnet power, magnet power dump, quench heater power, and special instrumentation. Electrical connectors serve as interfaces for instrumentation and quench heater circuits. These connectors have to meet stringent requirements.

Antennae

NASA Image and Video Library

1999-12-09

Atlas Image mosaic, covering 7 x 7 on the sky of the interacting galaxies NGC 4038 and NGC 4039, better known as the Antennae, or Ring Tail galaxies. The two galaxies are engaged in a tug-of-war as they collide.

Effects of CSR Generated from Upstream Bends in a Laser Plasma Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, C.; Qiang, J.; Venturini, M.

The recent proposal [1] of a Laser Plasma Storage Ring (LPSR) envisions the use of a laser-plasma (LP) acceleration module to inject an electron beam into a compact 500 MeV storage ring. Electron bunches generated by LP methods are naturally very short (tens of femtoseconds), presenting peak currents on the order of 10 kA or higher. Of obvious concern is the impact of collective effects and in particular Coherent Synchrotron Radiation (CSR) on the beam dynamics in the storage ring. Available simulation codes (e.g. Elegant [2]) usually include transient CSR effects but neglect the contribution of radiation emitted from trailingmore » magnets. In a compact storage ring, with dipole magnets close to each other, cross talking between different magnets could in principle be important.In this note we investigate this effect for the proposed LPSR and show that, in fact, this effect is relatively small. However our analysis also indicates that CSR effects in general would be quite strong and deserve a a careful study.« less

Ring profiler: a new method for estimating tree-ring density for improved estimates of carbon storage

Treesearch

David W. Vahey; C. Tim Scott; J.Y. Zhu; Kenneth E. Skog

2012-01-01

Methods for estimating present and future carbon storage in trees and forests rely on measurements or estimates of tree volume or volume growth multiplied by specific gravity. Wood density can vary by tree ring and height in a tree. If data on density by tree ring could be obtained and linked to tree size and stand characteristics, it would be possible to more...

Storage rings, internal targets and PEP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, J.E.

Storage rings with internal targets are described, using PEP as an example. The difference between electrons and heavier particles such as protons, antiprotons, and heavy ions is also discussed because it raises possibilities of bypass insertions for more exotic experiments. PEP is compared to other rings in various contexts to verify the assertion that it is an ideal ring for many fundamental and practical applications that can be carried on simultaneously. (LEW)

ELISA - an electrostatic storage ring for low-energy ions

NASA Astrophysics Data System (ADS)

Pape Moeller, Soeren

1997-05-01

The design of a new type of storage ring for low-energy ions using electrostatic deflection and focusing devices is described. Electrostatic bends and quadrupoles are used since they are more efficient than magnetic ones for low-velocity heavy ions. Furthermore, electrostatic devices are more compact and easier to construct than magnetic devices. In comparison to an electromagnetic trap, one important advantage of the elecrostatic ring is the easy access to the circulating beam and its decay products. These and other features, e.g. no magnetic fields, makes such storage devices attractive for many atomic-physics experiments. Also neigboring fields as chemistry and biology might benefit from such an relatively inexpensive device. One important difference between an electrostatic and a magnetic ring is, that the longitudinal energy is not conserved for the electrostatic ring. The actual ring will have a race-track shape as defined by two straight sections each with two quadrupole doublets connected by 180-degrees bends. The bends will consist of 160-degrees spherical deflection plates surrounded by two parallel plate 10-degrees bends. The storage ring ELISA, currently being built, will have a circumference of 6 meters. The first beam tests will take place during summer 1996.

Beam scrubbing of beam pipes during the first commissioning of SuperKEKB

NASA Astrophysics Data System (ADS)

Suetsugu, Y.; Shibata, K.; Ishibashi, T.; Kanazawa, K.; Shirai, M.; Terui, S.; Hisamatsu, H.

2018-02-01

The first (Phase-1) commissioning of SuperKEKB-an electron-positron collider with asymmetric energies located at KEK, in Tsukuba, Japan-started in February 2016, after more than five years of upgrading work on KEKB, and successfully ended in June of the same year. This paper describes one major task of Phase-1 commissioning: beam scrubbing the surface of the beam pipes, to prepare them for a sufficiently long beam lifetime and low background noise in the next commissioning, when a new particle detector will be installed. The pressure rises per unit beam current (dP/dI [Pa A-1]) were continuously monitored, and the coefficient of photon-stimulated desorption (PSD), η [molecules photon-1], was evaluated in the arc sections. The value of η decreased steadily with the beam dose, as expected. For arc sections in the positron ring, where most of the beam pipes were newly fabricated, the decrease in η against the photon dose (D) was similar to that previously reported; that is: η ∝ D-0.5 ∼ 0.8. At high storage beam currents, the evolution of η was affected by gas desorption resulting from the multipacting of electrons-that is, the electron cloud effect (ECE), which is a phenomenon particular to high-intensity positron rings. For the arc sections in the electron ring, η also decreased smoothly with the photon dose D, approximately as ∝ D-0.8. Given that most of these beam pipes were reused from KEKB, the value of η was much lower than that of the positron ring, and also lower than that of the electron ring of KEKB from the early stages of D. This implies that the surface of the reused beam pipes remembered the conditions in the KEKB, which is a known memory effect. The results obtained for η are compared with those obtained in various other accelerators.

Beam diagnostics at high-intensity storage rings

NASA Astrophysics Data System (ADS)

Plum, Mike

1994-10-01

Beam diagnostics at high-intensity facilities feature their own special set of problems and characteristics, issues peculiar to high-intensity storage rings include beam loss, beam halos, extraction efficiency, beam in the gap, clearing electrodes, and beam-profile measurement. The Los Alamos Proton Storage Ring (PSR) is a nice example of a high-intensity storage ring. I will discuss in some detail three diagnostic systems currently in use at the PSR: the beam-loss-monitor system, the electron-clearing system, and the beam-in-the-gap monitor. Much of our discussion is inspired by the problems we have encountered and the useful things we have learned while commissioning and developing the PSR. Another inspiration is our work on the next-generation neutron-spallation source, also known as the National Center for Neutron Research (NCNR).

Model-independent and fast determination of optical functions in storage rings via multiturn and closed-orbit data

NASA Astrophysics Data System (ADS)

Riemann, Bernard; Grete, Patrick; Weis, Thomas

2011-06-01

Multiturn (or turn-by-turn) data acquisition has proven to be a new source of direct measurements for Twiss parameters in storage rings. On the other hand, closed-orbit measurements are a long-known tool for analyzing closed-orbit perturbations with conventional beam position monitor (BPM) systems and are necessarily available at every storage ring. This paper aims at combining the advantages of multiturn measurements and closed-orbit data. We show that only two multiturn BPMs and four correctors in one localized drift space in the storage ring (diagnostic drift) are sufficient for model-independent and absolute measuring of β and φ functions at all BPMs, including the conventional ones, instead of requiring all BPMs being equipped with multiturn electronics.

Study of Storage Ring Free-Electron Laser Using Experimental and Simulation Approaches

NASA Astrophysics Data System (ADS)

Jia, Botao

2011-12-01

The Duke electron storage ring, first commissioned in November of 1994, has been developed as a dedicated driver for storage ring free-electron lasers (SRFELs) operating in a wide wavelength range from infrared, to visible, to ultraviolet (UV) and vacuum ultraviolet (VUV). The storage ring has a long straight section for various insertion devices and can be operated in a wide energy range (0.25 GeV to 1.15 GeV). Commissioned in 1995, the first free-electron laser (FEL) on the Duke storage ring was the OK-4 FEL, an optical klystron with two planar undulators sandwiching a buncher magnet. In 2005, the OK-5 FEL with two helical undulators was commissioned. Operating four undulators---two OK-4 and two OK-5 undulators, the world's first distributed optical klystron FEL was brought to operation in 2005. Via Compton scattering of FEL photons and electrons in the storage ring, the Duke FEL drives the world's most powerful, nearly monochromatic, and polarized Compton gamma-ray source, the High Intensity Gamma-ray Source (HIgammaS). Today, a variety of configurations of the storage ring FELs at Duke have been used in a wide range of research areas from nuclear physics to biophysics, from chemical and medical research to industrial applications. The capability of accurately measuring the storage ring electron beam energy spread is crucial for understanding the longitudinal beam dynamics and the dynamics of the storage ring FEL. In this dissertation, we have successfully developed a noninvasive, versatile, and accurate method to measure the energy spread using optical klystron radiation. Novel numerical methods based upon the Gauss-Hermite expansion have been developed to treat both spectral broadening and modulation on an equal footing. Through properly configuring the optical klystron, this energy spread measurement method has a large dynamic range. In addition, a model-based scheme has been developed for correcting the electron beam emittance related inhomogeneous spectral broadening effect, to further enhance the accuracy of measuring the electron beam energy spread. Taking advantage of the direct measurement method of the electron beam energy spread, we have developed another novel technique to simultaneously measure the FEL power, electron beam energy spread, and other beam parameters. This allowed us to study the FEL power in a systematic manner for the first time. Based on the experimental findings and results of the theoretical predictions, we have proposed a compact formula to predict the FEL power using only the knowledge of electron beam current, beam energy, and bunch length. As part of the dissertation work, we have developed a self-consistent numerical model to study the storage ring FEL. The simulation program models the electron beam propagation along the storage ring, multi-turn FEL interaction in the undulators, gradual intra-cavity optical power buildup, etc. This simulation code captures the main features of a storage ring FEL at different time and space scales. The simulated FEL gain has been benchmarked against measured gain and calculated gain with good agreement. The simulation package can provide comprehensive information about the FEL gain, optical pulse growth, electron beam properties, etc. In the near future, we plan to further improve the simulation model, by including additional physics effects such as microwave instability, to make it a more useful tool for FEL research.

Single-pass BPM system of the Photon Factory storage ring.

PubMed

Honda, T; Katoh, M; Mitsuhashi, T; Ueda, A; Tadano, M; Kobayashi, Y

1998-05-01

At the 2.5 GeV ring of the Photon Factory, a single-pass beam-position monitor (BPM) system is being prepared for the storage ring and the beam transport line. In the storage ring, the injected beam position during the first several turns can be measured with a single injection pulse. The BPM system has an adequate performance, useful for the commissioning of the new low-emittance lattice. Several stripline BPMs are being installed in the beam transport line. The continuous monitoring of the orbit in the beam transport line will be useful for the stabilization of the injection energy as well as the injection beam orbit.

Photon generator

DOEpatents

Srinivasan-Rao, Triveni

2002-01-01

A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

CEPC booster design study

DOE PAGES

Bian, Tianjian; Gao, Jie; Zhang, Chuang; ...

2017-12-10

In September 2012, Chinese scientists proposed a Circular Electron Positron Collider (CEPC) in China at 240 GeV center-of-mass energy for Higgs studies. The booster provides 120 GeV electron and positron beams to the CEPC collider for top-up injection at 0.1 Hz. The design of the full energy booster ring of the CEPC is a challenge. The ejected beam energy is 120 GeV and the injected beam energy is 6 GeV. Here in this paper we describe two alternative schemes, the wiggler bend scheme and the normal bend scheme. For the wiggler bend scheme, we propose to operate the booster ringmore » as a large wiggler at low energy and as a normal ring at high energy to avoid the problem of very low dipole magnet fields. Finally, for the normal bend scheme, we implement the orbit correction to correct the earth field.« less

Fission and fusion scenarios for magnetic microswimmer clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guzmán-Lastra, Francisca; Kaiser, Andreas; Löwen, Hartmut

Fission and fusion processes of particle clusters occur in many areas of physics and chemistry from subnuclear to astronomic length scales. Here we study fission and fusion of magnetic microswimmer clusters as governed by their hydrodynamic and dipolar interactions. Rich scenarios are found that depend crucially on whether the swimmer is a pusher or a puller. In particular a linear magnetic chain of pullers is stable while a pusher chain shows a cascade of fission (or disassembly) processes as the self-propulsion velocity is increased. Contrarily, magnetic ring clusters show fission for any type of swimmer. Moreover, we find a plethoramore » of possible fusion (or assembly) scenarios if a single swimmer collides with a ringlike cluster and two rings spontaneously collide. Lastly, our predictions are obtained by computer simulations and verifiable in experiments on active colloidal Janus particles and magnetotactic bacteria.« less

CEPC booster design study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bian, Tianjian; Gao, Jie; Zhang, Chuang

In September 2012, Chinese scientists proposed a Circular Electron Positron Collider (CEPC) in China at 240 GeV center-of-mass energy for Higgs studies. The booster provides 120 GeV electron and positron beams to the CEPC collider for top-up injection at 0.1 Hz. The design of the full energy booster ring of the CEPC is a challenge. The ejected beam energy is 120 GeV and the injected beam energy is 6 GeV. Here in this paper we describe two alternative schemes, the wiggler bend scheme and the normal bend scheme. For the wiggler bend scheme, we propose to operate the booster ringmore » as a large wiggler at low energy and as a normal ring at high energy to avoid the problem of very low dipole magnet fields. Finally, for the normal bend scheme, we implement the orbit correction to correct the earth field.« less

Fission and fusion scenarios for magnetic microswimmer clusters

DOE PAGES

Guzmán-Lastra, Francisca; Kaiser, Andreas; Löwen, Hartmut

2016-11-22

Fission and fusion processes of particle clusters occur in many areas of physics and chemistry from subnuclear to astronomic length scales. Here we study fission and fusion of magnetic microswimmer clusters as governed by their hydrodynamic and dipolar interactions. Rich scenarios are found that depend crucially on whether the swimmer is a pusher or a puller. In particular a linear magnetic chain of pullers is stable while a pusher chain shows a cascade of fission (or disassembly) processes as the self-propulsion velocity is increased. Contrarily, magnetic ring clusters show fission for any type of swimmer. Moreover, we find a plethoramore » of possible fusion (or assembly) scenarios if a single swimmer collides with a ringlike cluster and two rings spontaneously collide. Lastly, our predictions are obtained by computer simulations and verifiable in experiments on active colloidal Janus particles and magnetotactic bacteria.« less

REQUIREMENTS AND GUIDELINES FOR NSLS EXPERIMENTAL BEAM LINE VACUUM SYSTEMS-REVISION B.

DOE Office of Scientific and Technical Information (OSTI.GOV)

FOERSTER,C.

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas aftermore » a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, more energetic photons of the x-ray ring, beryllium windows are used at various beam line locations so that the monochromator, mirror box or sample chamber may be used in a helium atmosphere or rough vacuum. The window separates ring vacuum from the environment of the downstream beam line components. The stored beam lifetime in the storage rings and the maintenance of desirable reflection properties of optical surfaces depend upon hydrocarbon-free, ultra-high vacuum systems. Storage ring vacuum systems will operate at pressures of {approximately} 1 x 10{sup {minus}10} Torr without beam and {approximately} 1 x 10{sup {minus}9} Torr with beam. Systems are free of hydrocarbons in the sense that no pumps, valves, etc. containing organics are used. Components are all-metal, chemically cleaned and bakeable. To the extent that beam lines share a common vacuum with the storage ring, the same criteria will hold for beam line components. The design philosophy for NSLS beam lines is to use all-metal, hydrocarbon-free front end components and recommend that experimenters use this approach for common vacuum hardware downstream of front ends. O-ring-sealed valves, if used, are not permitted upstream of the monochromator exit aperture. It will be the responsibility of users to demonstrate that their experiment will not degrade the pressure or quality of the storage ring vacuum. As a matter of operating policy, all beam lines will be monitored for prescribed pressure and the contribution of high mass gases to this pressure each time a beam line has been opened to ring vacuum.« less

Low-emittance tuning of storage rings using normal mode beam position monitor calibration

NASA Astrophysics Data System (ADS)

Wolski, A.; Rubin, D.; Sagan, D.; Shanks, J.

2011-07-01

We describe a new technique for low-emittance tuning of electron and positron storage rings. This technique is based on calibration of the beam position monitors (BPMs) using excitation of the normal modes of the beam motion, and has benefits over conventional methods. It is relatively fast and straightforward to apply, it can be as easily applied to a large ring as to a small ring, and the tuning for low emittance becomes completely insensitive to BPM gain and alignment errors that can be difficult to determine accurately. We discuss the theory behind the technique, present some simulation results illustrating that it is highly effective and robust for low-emittance tuning, and describe the results of some initial experimental tests on the CesrTA storage ring.

Multipacting optimization of a 750 MHz rf dipole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delayen, Jean R.; Castillo, Alejandro

2014-12-01

Crab crossing schemes have been proposed to re-instate luminosity degradation due to crossing angles at the interaction points in next generation colliders to avoid the use of sharp bending magnets and their resulting large synchrotron radiation generation, highly undessirable in the detector region. The rf dipole has been considered for a different set of applications in several machines, both rings and linear colliders. We present in this paper a study of the effects on the multipacting levels and location depending on geometrical variations on the design for a crabbing/deflecting application in a high current (3/0.5 A), high repetition (750 MHz)more » electron/proton collider, as a matter to provide a comparison point for similar applications of rf dipoles.« less

An investigation of high-multiplicity gamma events in pp collisions with c.m. energies between 22 and 62 GeV

NASA Technical Reports Server (NTRS)

Dell, G. F.; Uto, H.; Yuan, L. C. L.; Amaldi, E.; Beneventano, M.; Borgia, B.; Pistilli, P.; Sestili, I.; Dooher, J.

1976-01-01

An experiment was conducted at the CERN intersecting storage rings using colliding proton beams to investigate high-multiplicity gamma-ray events. The objective of the study was to reveal certain features of multiple pion production as well as other possible mechanisms of gamma-ray production. The detector system consisted of ten planes of spark chambers, three scintillation counter hodoscopes and two arrays of lead-glass Cerenkov counters, the first array containing 16 counters and the second, 60 counters. The event trigger was obtained from the Cerenkov counters, and the energies in all the Cerenkov counters after trigger, as well as the information on all the charged particles given by the scintillation counters and spark chambers were recorded on magnetic tape. The relationship between the number of gamma-rays per event and the number of Cerenkov counters triggered by a neutral secondary was established by means of a Monte Carlo calculation.

Pseudo-single-bunch mode for a 100 MHz storage ring serving soft X-ray timing experiments

NASA Astrophysics Data System (ADS)

Olsson, T.; Leemann, S. C.; Georgiev, G.; Paraskaki, G.

2018-06-01

At many storage rings for synchrotron light production there is demand for serving both high-flux and timing users simultaneously. Today this is most commonly achieved by operating inhomogeneous fill patterns, but this is not preferable for rings that employ passive harmonic cavities to damp instabilities and increase Touschek lifetime. For these rings, inhomogeneous fill patterns could severely reduce the effect of the harmonic cavities. It is therefore of interest to develop methods to serve high-flux and timing users simultaneously without requiring gaps in the fill pattern. One such method is pseudo-single-bunch (PSB), where one bunch in the bunch train is kicked onto another orbit by a fast stripline kicker. The light emitted from the kicked bunch can then be separated by an aperture in the beamline. Due to recent developments in fast kicker design, PSB operation in multibunch mode is within reach for rings that operate with a 100 MHz RF system, such as the MAX IV and Solaris storage rings. This paper describes machine requirements and resulting performance for such a mode at the MAX IV 1.5 GeV storage ring. A solution for serving all beamlines is discussed as well as the consequences of beamline design and operation in the soft X-ray energy range.

A Model Describing Stable Coherent Synchrotron Radiation in Storage Rings

NASA Astrophysics Data System (ADS)

Sannibale, F.; Byrd, J. M.; Loftsdóttir, Á.; Venturini, M.; Abo-Bakr, M.; Feikes, J.; Holldack, K.; Kuske, P.; Wüstefeld, G.; Hübers, H.-W.; Warnock, R.

2004-08-01

We present a model describing high power stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), which enhances higher frequency coherent emission, and limits to stable emission due to an instability excited by the SR wakefield. It gives a quantitative explanation of several features of the recent observations of CSR at the BESSYII storage ring. We also use this model to optimize the performance of a source for stable CSR emission.

Construction and operation of a support facilities (Building 729) for operation/testing of a prototype accelerator/storage ring (XLS) and machine shop for the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-06-01

Proposed action is to construct at BNL a 5,600-ft[sup 2] support building, install and operate a prototypic 200 MeV accelerator and a prototypic 700 MeV storage ring within, and to construct and operate a 15 kV substation to power the building. The accelerator and storage ring would comprise the x-ray lithography source or XLS.

Construction and operation of a support facilities (Building 729) for operation/testing of a prototype accelerator/storage ring (XLS) and machine shop for the National Synchrotron Light Source at Brookhaven National Laboratory, Upton, New York. Environmental assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-06-01

Proposed action is to construct at BNL a 5,600-ft{sup 2} support building, install and operate a prototypic 200 MeV accelerator and a prototypic 700 MeV storage ring within, and to construct and operate a 15 kV substation to power the building. The accelerator and storage ring would comprise the x-ray lithography source or XLS.

High resolution monochromator for the VUV radiation from the DORIS storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saile, V.; Gurtler, P.; Koch, E.E.

1976-10-01

The unique properties of the DORIS storage ring at DESY as a synchroton radiation source are exploited for high resolution spectroscopy in the vacuum ultraviolet. We describe a new experimental set up with a 3-m normal incidence monochromator for wavelengths between 3000 A and 300 A (4 < or = h..omega.. < or = 40 eV) using a vertical dispersion plane. The storage ring provides a light flux intense and stable enough for rapid photoelectrical scanning of the spectra with a resolution of 0.03 A in first order. (AIP)

Design Study of an MBA Lattice for the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Decker, Glenn

2014-11-02

Recent interest in ultra-low-emittance designs for storage-ring-based synchrotron light sources has spurred a focused design effort on a multi-bend achromat (MBA) storage ring replacement for the Advanced Photon Source (APS). The APS is relatively large (1104 m circumference) and, as such, an upgrade to a fourth-generation storage ring holds the potential for a two to three order of magnitude enhancement of X-ray brightness due to the approximate inverse cubic scaling of emittance with the number of dipole bend magnets.

ACCELERATORS: Preliminary application of turn-by-turn data analysis to the SSRF storage ring

NASA Astrophysics Data System (ADS)

Chen, Jian-Hui; Zhao, Zhen-Tang

2009-07-01

There is growing interest in utilizing the beam position monitor turn-by-turn (TBT) data to debug accelerators. TBT data can be used to determine the linear optics, coupled optics and nonlinear behaviors of the storage ring lattice. This is not only a useful complement to other methods of determining the linear optics such as LOCO, but also provides a possibility to uncover more hidden phenomena. In this paper, a preliminary application of a β function measurement to the SSRF storage ring is presented.

How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97 - GeV / c Deuterons in a Storage Ring

DOE PAGES

Guidoboni, G.; Stephenson, E.; Andrianov, S.; ...

2016-07-28

Here, we observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10 -29 $e$ cm.

Dielectronic recombination experiments at the storage rings: From the present CSR to the future HIAF

NASA Astrophysics Data System (ADS)

Huang, Z. K.; Wen, W. Q.; Xu, X.; Wang, H. B.; Dou, L. J.; Chuai, X. Y.; Zhu, X. L.; Zhao, D. M.; Li, J.; Ma, X. M.; Mao, L. J.; Yang, J. C.; Yuan, Y. J.; Xu, W. Q.; Xie, L. Y.; Xu, T. H.; Yao, K.; Dong, C. Z.; Zhu, L. F.; Ma, X.

2017-10-01

Dielectronic recombination (DR) experiments of highly charged ions at the storage rings have been developed as a precision spectroscopic tool to investigate the atomic structure as well as nuclear properties of stable and unstable nuclei. The DR experiment on lithium-like argon ions was successfully performed at main Cooler Storage Ring (CSRm) at Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex. The DR experiments on heavy highly charged ions and even radioactive ions are currently under preparation at the experimental Cooler Storage Ring (CSRe) at HIRFL. The current status of DR experiments at the CSRm and the preparation of the DR experiments at the CSRe are presented. In addition, an overview of DR experiments by employing an electron cooler and a separated ultra-cold electron target at the upcoming High Intensity heavy ion Accelerator Facility (HIAF) will be given.

High-energy accelerator for beams of heavy ions

DOEpatents

Martin, Ronald L.; Arnold, Richard C.

1978-01-01

An apparatus for accelerating heavy ions to high energies and directing the accelerated ions at a target comprises a source of singly ionized heavy ions of an element or compound of greater than 100 atomic mass units, means for accelerating the heavy ions, a storage ring for accumulating the accelerated heavy ions and switching means for switching the heavy ions from the storage ring to strike a target substantially simultaneously from a plurality of directions. In a particular embodiment the heavy ion that is accelerated is singly ionized hydrogen iodide. After acceleration, if the beam is of molecular ions, the ions are dissociated to leave an accelerated singly ionized atomic ion in a beam. Extraction of the beam may be accomplished by stripping all the electrons from the atomic ion to switch the beam from the storage ring by bending it in magnetic field of the storage ring.

Injection envelope matching in storage rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minty, M.G.; Spence, W.L.

1995-05-01

The shape and size of the transverse phase space injected into a storage ring can be deduced from turn-by-turn measurements of the transient behavior of the beam envelope in the ring. Envelope oscillations at 2 x the {beta}-tron frequency indicate the presence of a {beta}-mismatch, while envelope oscillations at the {beta}-tron frequency are the signature of a dispersion function mismatch. Experiments in injection optimization using synchrotron radiation imaging of the beam and a fast-gated camera at the SLC damping rings are reported.

Injection envelope matching in storage rings

NASA Astrophysics Data System (ADS)

Minty, M. G.; Spence, W. L.

1995-05-01

The shape and size of the transverse phase space injected into a storage ring can be deduced from turn-by-turn measurements of the transient behavior of the beam envelope in the ring. Envelope oscillations at 2 x the beta-tron frequency indicate the presence of a beta-mismatch, while envelope oscillations at the beta-tron frequency are the signature of a dispersion function mismatch. Experiments in injection optimization using synchrotron radiation imaging of the beam and a fast-gated camera at the SLC damping rings are reported.

Variable Permanent Magnet Quadrupole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihara, T.; Iwashita, Y.; /Kyoto U.

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four partsmore » and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.« less

Status and outlook of the CRYRING@ESR project

NASA Astrophysics Data System (ADS)

Geithner, W.; Andelkovic, Z.; Beck, D.; Bräuning, H.; Bräuning-Demian, A.; Danared, H.; Dimopoulou, C.; Engström, M.; Fedotova, S.; Gorda, O.; Herfurth, F.; Hess, R.; Källberg, A.; Kleffner, C.; Kotovskiy, N.; Kraus, I.; Lestinsky, M.; Litvinov, S.; Nolden, F.; Reiter, A.; Sieber, T.; Steck, M.; Vorobyev, G.

2017-11-01

Once operational, CRYRING@ESR will store and decelerate ions delivered by the experimental storage ring ESR at energies well below those of ESR. In addition to that, CRYRING@ESR has an electron cooler operating with an ultracold electron beam, allowing to provide cooled ion beams for precision experiments. These ions will be delivered to a broad range of experiments presently in preparation; either in-ring or extracted to a dedicated beamline for experiments. An overview and status report of the installation and commissioning of the CRYRING-@ESR storage ring for highly charged ions at the GSI Helmholtzzentrum für Schwerionenforschung is presented. The installation of this storage ring started in 2014 and was completing end of 2016, when this publication was written.

Recent progress in neutrino factory and muon collider research within the Muon Collaboration

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. M. Alsharoa; Charles M. Ankenbrandt; Muzaffer Atac

2003-08-01

We describe the status of our effort to realize a first neutrino factory and the progress made in understanding the problems associated with the collection and cooling of muons towards that end. We summarize the physics that can be done with neutrino factories as well as with intense cold beams of muons. The physics potential of muon colliders is reviewed, both as Higgs Factories and compact high energy lepton colliders. The status and timescale of our research and development effort is reviewed as well as the latest designs in cooling channels including the promise of ring coolers in achieving longitudinalmore » and transverse cooling simultaneously. We detail the efforts being made to mount an international cooling experiment to demonstrate the ionization cooling of muons.« less

Status of the Frankfurt low energy electrostatic storage ring (FLSR)

NASA Astrophysics Data System (ADS)

King, F.; Kruppi, T.; Müller, J.; Dörner, R.; Schmidt, L. Ph H.; Schmidt-Böcking, H.; Stiebing, K. E.

2015-11-01

Frankfurt low-energy storage ring (FLSR) is an electrostatic storage ring for low-energy ions up to q · 80 keV (q being the ion charge state) at Institut für Kernphysik der Goethe-Universität, Frankfurt am Main, Germany. It has especially been designed to provide a basis for experiments on the dynamics of ionic and molecular collisions in complete kinematics, as well as for high precision and time resolved laser spectroscopy. The ring has ‘racetrack’ geometry with a circumference of 14.23 m. It comprises four experimental/diagnostic sections with regions of enhanced ion density (interaction regions). First beam has successfully been stored in FLSR in summer 2013. Since then the performance of the ring has continuously been improved and an electron target for experiments on dissociative recombination has been installed in one of the experimental sections.

Analysis and correction of linear optics errors, and operational improvements in the Indus-2 storage ring

NASA Astrophysics Data System (ADS)

Husain, Riyasat; Ghodke, A. D.

2017-08-01

Estimation and correction of the optics errors in an operational storage ring is always vital to achieve the design performance. To achieve this task, the most suitable and widely used technique, called linear optics from closed orbit (LOCO) is used in almost all storage ring based synchrotron radiation sources. In this technique, based on the response matrix fit, errors in the quadrupole strengths, beam position monitor (BPM) gains, orbit corrector calibration factors etc. can be obtained. For correction of the optics, suitable changes in the quadrupole strengths can be applied through the driving currents of the quadrupole power supplies to achieve the desired optics. The LOCO code has been used at the Indus-2 storage ring for the first time. The estimation of linear beam optics errors and their correction to minimize the distortion of linear beam dynamical parameters by using the installed number of quadrupole power supplies is discussed. After the optics correction, the performance of the storage ring is improved in terms of better beam injection/accumulation, reduced beam loss during energy ramping, and improvement in beam lifetime. It is also useful in controlling the leakage in the orbit bump required for machine studies or for commissioning of new beamlines.

Symmetrical collision of multiple vortex rings

NASA Astrophysics Data System (ADS)

Hernández, R. H.; Reyes, T.

2017-10-01

In this work, we investigate the motion, interaction, and simultaneous collision between many initially stable vortex rings arranged symmetrically in two initial configurations, three and six rings making an angle of 60 and 120° between their straight path lines, respectively. We report results for laminar vortex rings in air obtained through numerical simulations of the ring velocity, pressure, and vorticity fields, both in free flight and during the entire collision. Each collision was studied for small Reynolds numbers R e <1 03 based on both the self-induced velocity and diameter of the ring. The case of three rings produces secondary vortical structures formed by laterally expanding dipolar arms with top and bottom secondary vortex rings. The case of six colliding rings produces, as secondary structures, two big rings moving in opposite directions, a process that reminds us of the head-on collision of two rings [T. T. Lim and T. B. Nickels, "Instability and reconnection in the head-on collision of two vortex rings," Nature 357, 225-227 (1992)] under a hypothetical time reversal transformation. Both collisions display a characteristic kinetic energy evolution where mean collision stages can be identified within the range of Reynolds numbers investigated here.

INJECTION OPTICS FOR THE JLEIC ION COLLIDER RING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morozov, Vasiliy; Derbenev, Yaroslav; Lin, Fanglei

2016-05-01

The Jefferson Lab Electron-Ion Collider (JLEIC) will accelerate protons and ions from 8 GeV to 100 GeV. A very low beta function at the Interaction Point (IP) is needed to achieve the required luminosity. One consequence of the low beta optics is that the beta function in the final focusing (FF) quadrupoles is extremely high. This leads to a large beam size in these magnets as well as strong sensitivity to errors which limits the dynamic aperture. These effects are stronger at injection energy where the beam size is maximum, and therefore very large aperture FF magnets are required tomore » allow a large dynamic aperture. A standard solution is a relaxed injection optics with IP beta function large enough to provide a reasonable FF aperture. This also reduces the effects of FF errors resulting in a larger dynamic aperture at injection. We describe the ion ring injection optics design as well as a beta-squeeze transition from the injection to collision optics.« less

ION BEAM POLARIZATION DYNAMICS IN THE 8 GEV BOOSTER OF THE JLEIC PROJECT AT JLAB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondratenko, A. M.; Kondratenko, M. A.; Morozov, Vasiliy

2016-05-01

In the Jefferson Lab’s Electron-Ion Collider (JLEIC) project, an injector of polarized ions into the collider ring is a superconducting 8 GeV booster. Both figure-8 and racetrack booster versions were considered. Our analysis showed that the figure-8 ring configuration allows one to preserve the polarization of any ion species during beam acceleration using only small longitudinal field with an integral less than 0.5 Tm. In the racetrack booster, to pre-serve the polarization of ions with the exception of deu-terons, it suffices to use a solenoidal Siberian snake with a maximum field integral of 30 Tm. To preserve deuteron polarization, wemore » propose to use arc magnets for the race-track booster structure with a field ramp rate of the order of 1 T/s. We calculate deuteron and proton beam polari-zations in both the figure-8 and racetrack boosters includ-ing alignment errors of their magnetic elements using the Zgoubi code.« less

Compensation Techniques in Accelerator Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayed, Hisham Kamal

2011-05-01

Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Twomore » problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.« less

Picosecond, tunable, high-brightness hard x-ray inverse Compton source at Duke storage ring

NASA Astrophysics Data System (ADS)

Litvinenko, Vladimir N.; Wu, Ying; Burnham, Bentley; Barnett, Genevieve A.; Madey, John M. J.

1995-09-01

We suggest a state-of-the art x-ray source using a compact electron storage ring with modest energy (less than 1 GeV) and a high power mm-wave as an undulator. A source of this type has x-ray energies and brightness comparable with third generation synchrotron light sources while it can be very compact and fit in a small university or industrial laboratory or hospital. We propose to operate an isochronous mm-wave FEL and a hard x-ray inverse Compton source at the Duke storage ring to test this concept. Resonant FEL conditions for the mm- wave will be provided by the off-axis interaction with an electromagnetic wave. A special optical resonator with holes for the e-beam is proposed for pumping a hard x-ray inverse Compton source with very high brightness. Simulation results of mm-wave FEL operation of the Duke storage ring are discussed. Expected performance of mm-wave FEL and hard x-ray inverse Compton source are presented.

The Storage Ring Proton EDM Experiment

NASA Astrophysics Data System (ADS)

Semertzidis, Yannis; Storage Ring Proton EDM Collaboration

2014-09-01

The storage ring pEDM experiment utilizes an all-electric storage ring to store ~1011 longitudinally polarized protons simultaneously in clock-wise and counter-clock-wise directions for 103 seconds. The radial E-field acts on the proton EDM for the duration of the storage time to precess its spin in the vertical plane. The ring lattice is optimized to reduce intra-beam scattering, increase the statistical sensitivity and reduce the systematic errors of the method. The main systematic error is a net radial B-field integrated around the ring causing an EDM-like vertical spin precession. The counter-rotating beams sense this integrated field and are vertically shifted by an amount, which depends on the strength of the vertical focusing in the ring, thus creating a radial B-field. Modulating the vertical focusing at 10 kHz makes possible the detection of this radial B-field by a SQUID-magnetometer (SQUID-based BPM). For a total number of n SQUID-based BPMs distributed around the ring the effectiveness of the method is limited to the N = n /2 harmonic of the background radial B-field due to the Nyquist sampling theorem limit. This limitation establishes the requirement to reduce the maximum radial B-field to 0.1-1 nT everywhere around the ring by layers of mu-metal and aluminum vacuum tube. The metho's sensitivity is 10-29 e .cm , more than three orders of magnitude better than the present neutron EDM experimental limit, making it sensitive to SUSY-like new physics mass scale up to 300 TeV.

Dose estimates for the 1104 m APS storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moe, H.J.

1989-06-01

The estimated dose equivalent rates outside the shielded storage ring, and the estimated annual dose equivalent to members of the public due to direct radiation and skyshine from the ring, have been recalculated. The previous estimates found in LS-84 (MOE 87) and cited in the 1987 Conceptual Design Report of the APS (ANL 87) required revision because of changes in the ring circumference and in the proposed location of the ring with respect to the nearest site boundary. The values assumed for the neutron quality factors were also overestimated (by a factor of 2) in the previous computation, and themore » correct values have been used for this estimate. The methodology used to compute dose and dose rate from the storage ring is the same as that used in LS-90 (MOE 87a). The calculations assumed 80 cm thick walls of ordinary concrete (or the shielding equivalent of this) and a roof thickness of 1 meter of ordinary concrete. The circumference of the ring was increased to 1,104 m, and the closest distance to the boundary was taken as 140 m. The recalculation of the skyshine component used the same methodology as that used in LS-84.« less

Perspectives on micropole undulators in synchrotron radiation technology

NASA Astrophysics Data System (ADS)

Tatchyn, Roman; Csonka, Paul; Toor, Arthur

1989-07-01

Micropole undulators promise to advance synchrotron radiation (SR) technology in two distinct ways. The first is in the development of economical, low-energy storage rings, or linacs, as soft x-ray sources, and the second is in the opening up of gamma-ray spectral ranges on high-energy storage rings. In this paper the promise and current status of micropole undulator (MPU) technology are discussed, and a review of some practical obstacles to the implementation of MPU's on present-day storage rings is given. Some successful results of recent performance measurements of micropole undulators on the Lawrence Livermore National Laboratory linac are briefly summarized.

Analyses of 476 MHz and 952 MHz Crab Cavities for JLAB Electron Ion Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, HyeKyoung; Castilla, Alejandro; Delayen, Jean R.

2016-05-01

The Center for Accelerator Science at Old Dominion University has designed, fabricated and successfully tested a crab cavity for Electron Ion Collider at Jefferson Lab (JLEIC) [1]. This proof-of-principle cavity was based on the earlier MEIC design which used 748.5 MHz RF system. The updated JLEIC (called MEIC earlier) design [2] utilizes the components from PEP-II. It results in the change on the bunch repetition rate of stored beam to 476.3 MHz. The ion ring collider will eventually require 952.6 MHz crab cavities. This paper will present the analyses of crab cavities of both 476 MHz and 952 MHz options.more » It compares advantages and disadvantages of the options which provide the JLEIC design team important technical information for a system down selection.« less

Data Access Based on a Guide Map of the Underwater Wireless Sensor Network

PubMed Central

Wei, Zhengxian; Song, Min; Yin, Guisheng; Wang, Hongbin; Cheng, Albert M. K.

2017-01-01

Underwater wireless sensor networks (UWSNs) represent an area of increasing research interest, as data storage, discovery, and query of UWSNs are always challenging issues. In this paper, a data access based on a guide map (DAGM) method is proposed for UWSNs. In DAGM, the metadata describes the abstracts of data content and the storage location. The center ring is composed of nodes according to the shortest average data query path in the network in order to store the metadata, and the data guide map organizes, diffuses and synchronizes the metadata in the center ring, providing the most time-saving and energy-efficient data query service for the user. For this method, firstly the data is stored in the UWSN. The storage node is determined, the data is transmitted from the sensor node (data generation source) to the storage node, and the metadata is generated for it. Then, the metadata is sent to the center ring node that is the nearest to the storage node and the data guide map organizes the metadata, diffusing and synchronizing it to the other center ring nodes. Finally, when there is query data in any user node, the data guide map will select a center ring node nearest to the user to process the query sentence, and based on the shortest transmission delay and lowest energy consumption, data transmission routing is generated according to the storage location abstract in the metadata. Hence, specific application data transmission from the storage node to the user is completed. The simulation results demonstrate that DAGM has advantages with respect to data access time and network energy consumption. PMID:29039757

Data Access Based on a Guide Map of the Underwater Wireless Sensor Network.

PubMed

Wei, Zhengxian; Song, Min; Yin, Guisheng; Song, Houbing; Wang, Hongbin; Ma, Xuefei; Cheng, Albert M K

2017-10-17

Underwater wireless sensor networks (UWSNs) represent an area of increasing research interest, as data storage, discovery, and query of UWSNs are always challenging issues. In this paper, a data access based on a guide map (DAGM) method is proposed for UWSNs. In DAGM, the metadata describes the abstracts of data content and the storage location. The center ring is composed of nodes according to the shortest average data query path in the network in order to store the metadata, and the data guide map organizes, diffuses and synchronizes the metadata in the center ring, providing the most time-saving and energy-efficient data query service for the user. For this method, firstly the data is stored in the UWSN. The storage node is determined, the data is transmitted from the sensor node (data generation source) to the storage node, and the metadata is generated for it. Then, the metadata is sent to the center ring node that is the nearest to the storage node and the data guide map organizes the metadata, diffusing and synchronizing it to the other center ring nodes. Finally, when there is query data in any user node, the data guide map will select a center ring node nearest to the user to process the query sentence, and based on the shortest transmission delay and lowest energy consumption, data transmission routing is generated according to the storage location abstract in the metadata. Hence, specific application data transmission from the storage node to the user is completed. The simulation results demonstrate that DAGM has advantages with respect to data access time and network energy consumption.

Compact Storage Ring for an X-Ray Source

NASA Astrophysics Data System (ADS)

Ovchinnikova, L.; Shvedunov, V.; Ivanov, K.

2017-12-01

We propose a new design of a compact storage ring for a source of X-ray radiation on the basis of reverse Thomson scattering of laser radiation by electrons with the energy of 35-50 MeV, which has small number of optical elements and a significant clear space for the placement of a beam injection-extraction system and a RF cavity. The original laser cavity layout has been considered. The ring dynamic aperture after correction of chromaticity and a second-order dispersion function is sufficient for the injection and stable circulation of an electron bunch in the ring.

Burton Richter, Storage Rings, and the J/psi Particle

Science.gov Websites

[SLAC's] Technical Director, [Richter] became Director ... from 1984 through 1999. During his tenure, SLAC Limits of Quantum Electro-dynamics, DOE Technical Report, June 1959 Design Considerations for High Energy Electron -- Positron Storage Rings, DOE Technical Report, November 1966 Inclusive Yields of pi+, pi-, K

End-to-end 9-D polarized bunch transport in eRHIC energy-recovery recirculator, some aspects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meot, F.; Meot, F.; Brooks, S.

2015-05-03

This paper is a brief overview of some of the numerous beam and spin dynamics investigations undertaken in the framework of the design of the FFAG based electron energy recovery re-circulator ring of the eRHIC electron-ion collider project

Mechanical capacitor

NASA Technical Reports Server (NTRS)

Kirk, J. A.; Studer, P. A.; Evans, H. E.

1976-01-01

A new energy storage system (the mechanical capacitor), using a spokeless magnetically levitated composite ring rotor, is described and design formulas for sizing the components are presented. This new system is configured around a permanent magnet (flux biased) suspension which has active servo control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of the stationary armature coils is proposed. There is no mechanical contact with the rotating spokeless ring; therefore, long life and near zero rundown losses are projected. A 7-kW h system is sized to demonstrate feasibility. A literature review of flywheel energy storage systems is also presented and general formulas are developed for comparing rotor geometries.

MULTI-OBJECTIVE ONLINE OPTIMIZATION OF BEAM LIFETIME AT APS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yipeng

In this paper, online optimization of beam lifetime at the APS (Advanced Photon Source) storage ring is presented. A general genetic algorithm (GA) is developed and employed for some online optimizations in the APS storage ring. Sextupole magnets in 40 sectors of the APS storage ring are employed as variables for the online nonlinear beam dynamics optimization. The algorithm employs several optimization objectives and is designed to run with topup mode or beam current decay mode. Up to 50\\% improvement of beam lifetime is demonstrated, without affecting the transverse beam sizes and other relevant parameters. In some cases, the top-upmore » injection efficiency is also improved.« less

National Synchrotron Light Source annual report 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulbert, S.L.; Lazarz, N.M.

1992-04-01

This report discusses the following research conducted at NSLS: atomic and molecular science; energy dispersive diffraction; lithography, microscopy and tomography; nuclear physics; UV photoemission and surface science; x-ray absorption spectroscopy; x-ray scattering and crystallography; x-ray topography; workshop on surface structure; workshop on electronic and chemical phenomena at surfaces; workshop on imaging; UV FEL machine reviews; VUV machine operations; VUV beamline operations; VUV storage ring parameters; x-ray machine operations; x-ray beamline operations; x-ray storage ring parameters; superconducting x-ray lithography source; SXLS storage ring parameters; the accelerator test facility; proposed UV-FEL user facility at the NSLS; global orbit feedback systems; and NSLSmore » computer system.« less

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-05-13

Here, we propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. Finally, the method has been successfully demonstrated on the NSLS-II storage ring.

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-08-01

We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. Furthermore, the fitting results are used for lattice correction. Our method has been successfully demonstrated on the NSLS-II storage ring.

A method for simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xi; Huang, Xiaobiao

2016-08-01

We propose a method to simultaneously correct linear optics errors and linear coupling for storage rings using turn-by-turn (TbT) beam position monitor (BPM) data. The independent component analysis (ICA) method is used to isolate the betatron normal modes from the measured TbT BPM data. The betatron amplitudes and phase advances of the projections of the normal modes on the horizontal and vertical planes are then extracted, which, combined with dispersion measurement, are used to fit the lattice model. The fitting results are used for lattice correction. The method has been successfully demonstrated on the NSLS-II storage ring.

NSLS-II storage ring insertion device and front-end commissioning and operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, G., E-mail: gwang@bnl.gov; Shaftan, T.; Amundsen, C.

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. During spring/ summer of 2014, the storage ring was commissioned up to 50 mA without insertion devices. In the fall of 2014, we began commissioning of the project beamlines, which included seven insertion devices on six ID ports. Beamlines IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1 consist of elliptically polarized undulator (EPU), damping wigglers (DW) and in-vacuum undulators (IVU) covering from VUV to hard x-ray range. In this paper, experience with commissioning and operation is discussed.more » We focus on reaching storage ring performance with IDs, including injection, design emittance, compensation of orbit distortions caused by ID residual field, source point stability, beam alignment and tools for control, monitoring and protection of the ring chambers from ID radiation.« less

Fluorescence decay of naphthalene studied in an electrostatic storage ring, the Mini-Ring

NASA Astrophysics Data System (ADS)

Martin, S.; Matsumoto, J.; Kono, N.; Ji, M.-C.; Brédy, R.; Bernard, J.; Cassimi, A.; Chen, L.

2017-10-01

The cooling of naphthalene cations (C10H8)+ has been studied in a compact electrostatic ion storage ring, the Mini-Ring. A nano second laser pulse of 532 nm (2.33 eV) was used to probe the internal energy distribution every millisecond during the storage time up to 5 ms. The evolution of the internal energy distribution of the stored ions was simulated with a model taking into account the dissociation and the radiative decay processes. Calculated decay curves were fitted to the corresponding laser induced neutral decays. For a laser power of 200 μJ/pulse, a good agreement between experiment and modeling was found using an initial Gaussian energy distribution centered to 5.9 eV and a fluorescence decay rate varying from 200 to 300 s-1 in the energy range from 6 to 7 eV. This fast decay was attributed to the delayed Poincaré fluorescence process.

Charge shielding in the In-situ Storage Image Sensor for a vertex detector at the ILC

NASA Astrophysics Data System (ADS)

Zhang, Z.; Stefanov, K. D.; Bailey, D.; Banda, Y.; Buttar, C.; Cheplakov, A.; Cussans, D.; Damerell, C.; Devetak, E.; Fopma, J.; Foster, B.; Gao, R.; Gillman, A.; Goldstein, J.; Greenshaw, T.; Grimes, M.; Halsall, R.; Harder, K.; Hawes, B.; Hayrapetyan, K.; Heath, H.; Hillert, S.; Jackson, D.; Pinto Jayawardena, T.; Jeffery, B.; John, J.; Johnson, E.; Kundu, N.; Laing, A.; Lastovicka, T.; Lau, W.; Li, Y.; Lintern, A.; Lynch, C.; Mandry, S.; Martin, V.; Murray, P.; Nichols, A.; Nomerotski, A.; Page, R.; Parkes, C.; Perry, C.; O'Shea, V.; Sopczak, A.; Tabassam, H.; Thomas, S.; Tikkanen, T.; Velthuis, J.; Walsh, R.; Woolliscroft, T.; Worm, S.

2009-08-01

The Linear Collider Flavour Identification (LCFI) collaboration has successfully developed the first prototype of a novel particle detector, the In-situ Storage Image Sensor (ISIS). This device ideally suits the challenging requirements for the vertex detector at the future International Linear Collider (ILC), combining the charge storing capabilities of the Charge-Coupled Devices (CCD) with readout commonly used in CMOS imagers. The ISIS avoids the need for high-speed readout and offers low power operation combined with low noise, high immunity to electromagnetic interference and increased radiation hardness compared to typical CCDs. The ISIS is one of the most promising detector technologies for vertexing at the ILC. In this paper we describe the measurements on the charge-shielding properties of the p-well, which is used to protect the storage register from parasitic charge collection and is at the core of device's operation. We show that the p-well can suppress the parasitic charge collection by almost two orders of magnitude, satisfying the requirements for the application.

A nanofabricated wirescanner with free standing wires: Design, fabrication and experimental results

NASA Astrophysics Data System (ADS)

Veronese, M.; Grulja, S.; Penco, G.; Ferianis, M.; Fröhlich, L.; Dal Zilio, S.; Greco, S.; Lazzarino, M.

2018-05-01

Measuring the transverse size of electron beams is of crucial importance in modern accelerators, from large colliders to free electron lasers to storage rings. For this reason several kind of beam instrumentation have been developed such as optical transition radiation screens, scintillating screens, laser scanners and wire scanners. The last ones although providing only a multishot profile in one plane have demonstrated a very high resolution. Wirescanners employ thin wires with typical thickness of the order of tens of microns that are scanned across the beam, whilst ionizing radiation generated from the impact of the electrons with the wires is detected. In this paper we describe a new approach to wirescanners design based on nanofabrication technologies opening new possibilities in term of wire shape, size, material and thickness with potential for sub-micron resolution and increase flexibility for instrumentation designers. We present a device fitted with nanofabricated wires and its fabrication process. We also report the measurements performed on the FERMI FEL electron beam with the goal of providing an online profile measurement without perturbing the FEL.

Investigation of beam self-polarization in the future e + e - circular collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gianfelice-Wendt, E.

The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the e +e - Future Circular Collider (FCC-e +e -) for Z and WW physics at 45 and 80 GeV beam energy respectively. Longitudinal beam polarization would benefit the Z peak physics program; however it is not essential and therefore it will be not investigated here. In this paper the possibility of self-polarized leptons is considered. As a result, preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified FCC-e +e - ring are presented.

Superstrong Adjustable Permanent Magnet for a Linear Collider Final Focus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihara, T.

A superstrong permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens for the linear collider because of its compactness and low power consumption. The first fabricated prototype of our PMQ achieved a 300T/m superstrong field gradient with a 100mm overall magnet radius and a 7mm bore radius, but a drawback is its fixed strength. Therefore, a second prototype of PMQ, whose strength is adjustable, was fabricated. Its strength adjustability is based on the ''double ring structure'', rotating subdivided magnet slices separately. This second prototype is being tested. Some of the early results are presented.

Investigation of beam self-polarization in the future e + e - circular collider

DOE PAGES

Gianfelice-Wendt, E.

2016-10-24

The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the e +e - Future Circular Collider (FCC-e +e -) for Z and WW physics at 45 and 80 GeV beam energy respectively. Longitudinal beam polarization would benefit the Z peak physics program; however it is not essential and therefore it will be not investigated here. In this paper the possibility of self-polarized leptons is considered. As a result, preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified FCC-e +e - ring are presented.

Investigation of beam self-polarization in the future e+e- circular collider

NASA Astrophysics Data System (ADS)

Gianfelice-Wendt, E.

2016-10-01

The use of resonant depolarization has been suggested for precise beam energy measurements (better than 100 keV) in the e+e- Future Circular Collider (FCC-e+e-) for Z and W W physics at 45 and 80 GeV beam energy respectively. Longitudinal beam polarization would benefit the Z peak physics program; however it is not essential and therefore it will be not investigated here. In this paper the possibility of self-polarized leptons is considered. Preliminary results of simulations in presence of quadrupole misalignments and beam position monitors (BPMs) errors for a simplified FCC-e+e- ring are presented.

Tree- Rings Link Climate and Carbon Storage in a Northern Mixed Hardwood Forest

NASA Astrophysics Data System (ADS)

Chiriboga, A.

2007-12-01

The terrestrial biosphere is a variable sink for atmospheric carbon dioxide. It is important to understand how carbon storage in trees is affected by natural climate variability to better characterize the sink. Quantifying the sensitivity of forest carbon storage to climate will improve carbon budgets and have implications for forest management practices. Here we explore how climate variability affects the ability of a northern mixed hardwood forest in Michigan to sequester atmospheric carbon dioxide in woody tissues. This site is ideal for studies of carbon sequestration; The University of Michigan Biological Station is an Ameriflux site, and has detailed meteorological and biometric records, as well as CO2 flux data. We have produced an 82- year aspen (Populus grandidentata) tree-ring chronology for this site, and measured ring widths at several heights up the bole. These measurements were used to estimate annual wood volume, which represents carbon allocated to aboveground carbon stores. Standard dendroclimatological techniques are used to identify environmental factors (e.g. temperature or precipitation) that drive tree-ring increment variability in the past century, and therefore annual carbon storage in this forest. Preliminary results show that marker years within the tree- ring chronology correspond with years that have cold spring temperatures. This suggests that trees at this site are temperature sensitive.

Beam Loss Measurements at the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Spickermann, Thomas

2005-06-01

During normal operation the Los Alamos Proton Storage Ring (PSR) accumulates up to 4ṡ1013 protons over 625μs with a repetition rate of 20 Hz, corresponding to a current of 125μA to the Lujan Neutron Science Center. Beam losses in the ring as well as in the extraction beam line and the subsequent activation of material are a limiting factor at these currents. Careful tuning of injection, ring and extraction line is paramount to limiting losses to acceptable levels. Losses are typically not uniform around the ring, but occur in significantly higher levels in certain "hot spots". Here I will report on losses related to the stripper foil which are the dominant source of losses in the ring. First results of a comparison with simulations will also be presented.

Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dees, Craig

2016-07-01

A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

An analog RF gap voltage regulation system for the Advanced Photon Source storage ring.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horan, D.

1999-04-13

An analog rf gap voltage regulation system has been designed and built at Argonne National Laboratory to maintain constant total storage ring rf gap voltage, independent of beam loading and cavity tuning effects. The design uses feedback control of the klystron mod-anode voltage to vary the amount of rf power fed to the storage ring cavities. The system consists of two independent feedback loops, each regulating the combined rf gap voltages of eight storage ring cavities by varying the output power of either one or two rf stations, depending on the mode of operation. It provides full operator control andmore » permissive logic to permit feedback control of the rf system output power only if proper conditions are met. The feedback system uses envelope-detected cavity field probe outputs as the feedback signal. Two different methods of combining the individual field probe signals were used to generate a relative DC level representing one-half of the total storage ring rf voltage, an envelope-detected vector sum of the field probe rf signals, and the DC sum of individual field probe envelope detector outputs. The merits of both methods are discussed. The klystron high-voltage power supply (HVPS) units are fitted with an analog interface for external control of the mod-anode voltage level, using a four-quadrant analog multiplier to modulate the HVPS mod-anode voltage regulator set-point in response to feedback system commands.« less

Observation of snake resonances at Relativistic Heavy Ion Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, M.; Ahrens, L.; Alekseev, I.G.

2010-09-27

The Siberian snakes are powerful tools in preserving polarization in high energy accelerators has been demonstrated at the Brookhaven Relativistic Heavy Ion Collider (RHIC). Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the Siberian snakes also introduce a new set of depolarization resonances, i.e. snake resonances as first discovered by Lee and Tepikian. The intrinsic spin resonances above 100 GeV are about a factor of two stronger than those below 100 GeV which raises the challenge to preserve the polarization up to 250 GeV. In 2009, polarized protonsmore » collided for the first time at the RHIC design store energy of 250 GeV. This paper presents the experimental measurements of snake resonances at RHIC. The plan for avoiding these resonances is also presented.« less

Analysis of Methods to Excite Head-Tail Motion Within the Cornell Electron Storage Ring

NASA Astrophysics Data System (ADS)

Gendler, Naomi; Billing, Mike; Shanks, Jim

The main accelerator complex at Cornell consists of two rings around which electrons and positrons move: the synchrotron, where the particles are accelerated to 5 GeV, and the Storage Ring, where the particles circulate a ta Þxed energy, guided by quadrupole and dipole magnets, with a steady energy due to a sinusoidal voltage source. Keeping the beam stable in the Storage Ring is crucial for its lifetime. A long-lasting, invariable beam means more accurate experiments, as well as brighter, more focused X-rays for use in the Cornell High Energy Synchrotron Source (CHESS). The stability of the electron and positron beams in the Cornell Electron Storage Ring (CESR) is important for the development of accelerators and for usage of the beam in X-ray science and accelerator physics. Bunch oscillations tend to enlarge the beam's cross section, making it less stable. We believe that one such oscillation is ``head-tail motion,'' where the bunch rocks back and forth on a pivot located at the central particle. In this project, we write a simulation of the bunch that induces head-tail motion with a vertical driver. We also excite this motion physically in the storage ring, and observe a deÞnite head-tail signal. In the experiment, we saw a deÞnite persistence of the drive-damp signal within a small band around the head-tail frequency, indicating that the head-tail frequency is a natural vertical mode of the bunch that was being excited. The signal seen in the experiment matched the signal seen in the simulation to within an order of magnitude.

Turning the LHC ring into a new physics search machine

NASA Astrophysics Data System (ADS)

Orava, Risto

2017-03-01

The LHC Collider Ring is proposed to be turned into an ultimate automatic search engine for new physics in four consecutive phases: (1) Searches for heavy particles produced in Central Exclusive Process (CEP): pp → p + X + p based on the existing Beam Loss Monitoring (BLM) system of the LHC; (2) Feasibility study of using the LHC Ring as a gravitation wave antenna; (3) Extensions to the current BLM system to facilitate precise registration of the selected CEP proton exit points from the LHC beam vacuum chamber; (4) Integration of the BLM based event tagging system together with the trigger/data acquisition systems of the LHC experiments to facilitate an on-line automatic search machine for the physics of tomorrow.

Modular focusing ring imaging Cherenkov detector for electron-ion collider experiments

NASA Astrophysics Data System (ADS)

Wong, C. P.; Alfred, M.; Allison, L.; Awadi, M.; Azmoun, B.; Barbosa, F.; Barion, L.; Bennett, J.; Brooks, W.; Butler, C.; Cao, T.; Chiu, M.; Cisbani, E.; Contalbrigo, M.; Datta, A.; Del Dotto, A.; Demarteau, M.; Durham, J. M.; Dzhygadlo, R.; Elder, T.; Fields, D.; Furletova, Y.; Gleason, C.; Grosse-Perdekamp, M.; Harris, J.; Haseler, T. O. S.; He, X.; van Hecke, H.; Horn, T.; Hruschka, A.; Huang, J.; Hyde, C.; Ilieva, Y.; Kalicy, G.; Kimball, M.; Kistenev, E.; Kulinich, Y.; Liu, M.; Majka, R.; McKisson, J.; Mendez, R.; Nadel-Turonski, P.; Park, K.; Peters, K.; Rao, T.; Pisani, R.; Qiang, Y.; Rescia, S.; Rossi, P.; Sarajlic, O.; Sarsour, M.; Schwarz, C.; Schwiening, J.; da Silva, C. L.; Smirnov, N.; Stien, H. D.; Stevens, J.; Sukhanov, A.; Syed, S.; Tate, A. C.; Toh, J.; Towell, C. L.; Towell, R. S.; Tsang, T.; Turisini, M.; Wagner, R.; Wang, J.; Woody, C.; Xi, W.; Xie, J.; Zhao, Z. W.; Zihlmann, B.; Zorn, C.

2017-11-01

A powerful new electron-ioncollider (EIC) has been recommended in the 2015 Long Range Plan for Nuclear Science for probing the partonic structure inside nucleons and nuclei with unprecedented precision and versatility [1]. EIC detectors are currently under development [2], all of which require hadron identification over a broad kinematic range. A prototype ring imaging Cherenkov detector has been developed for hadron identification in the momentum range from 3 GeV/c to 10 GeV/c. The key feature of this new detector is a compact and modular design, achieved by using aerogel as radiator and a Fresnel lens for ring focusing. In this paper, the results from a beam test of a prototype device at Fermilab are reported.

Beam vacuum system of Brookhaven`s muon storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hseuth, H.C.; Snydstrup, L.; Mapes, M.

1995-11-01

A storage ring with a circumference of 45 m is being built at Brookhaven to measure the g-2 value of the muons to an accuracy of 0.35 ppm.. The beam vacuum system of the storage ring will operate at 10{sup -7} Torr and has to be completely non-magnetic. It consists of twelve sector chambers. The chambers are constructed of aluminum and are approximately 3.5 m in length with a rectangular cross-section of 16.5 cm high by 45 cm at the widest point. The design features, fabrication techniques and cleaning methods for these chambers are described. The beam vacuum system willmore » be pumped by forty eight non-magnetic distributed ion pumps with a total pumping speed of over 2000 {ell}/sec. Monte Carlo simulations of the pressure distribution in the muon storage region are presented.« less

Corrections for a constant radial magnetic field in the muon \\varvec{g}-2 and electric-dipole-moment experiments in storage rings

NASA Astrophysics Data System (ADS)

Silenko, Alexander J.

2017-10-01

We calculate the corrections for constant radial magnetic field in muon {g}-2 and electric-dipole-moment experiments in storage rings. While the correction is negligible for the current generation of {g}-2 experiments, it affects the upcoming muon electric-dipole-moment experiment at Fermilab.

Loss-free method of charging accumulator rings

DOEpatents

Maschke, Alfred W.

1979-01-01

A method for the production of high current pulses of heavy ions having an atomic weight greater than 100. Also a linear accelerator based apparatus for carrying out said method. Pulses formed by the method of the subject invention are suitable for storage in a storage ring. The accumulated pulses may be used in inertial fusion apparatus.

National Synchrotron Light Source annual report 1991. Volume 1, October 1, 1990--September 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulbert, S.L.; Lazarz, N.M.

1992-04-01

This report discusses the following research conducted at NSLS: atomic and molecular science; energy dispersive diffraction; lithography, microscopy and tomography; nuclear physics; UV photoemission and surface science; x-ray absorption spectroscopy; x-ray scattering and crystallography; x-ray topography; workshop on surface structure; workshop on electronic and chemical phenomena at surfaces; workshop on imaging; UV FEL machine reviews; VUV machine operations; VUV beamline operations; VUV storage ring parameters; x-ray machine operations; x-ray beamline operations; x-ray storage ring parameters; superconducting x-ray lithography source; SXLS storage ring parameters; the accelerator test facility; proposed UV-FEL user facility at the NSLS; global orbit feedback systems; and NSLSmore » computer system.« less

Low emittance lattice for the storage ring of the Turkish Light Source Facility TURKAY

NASA Astrophysics Data System (ADS)

Nergiz, Z.; Aksoy, A.

2015-06-01

The TAC (Turkish Accelerator Center) project aims to build an accelerator center in Turkey. The first stage of the project is to construct an Infra-Red Free Electron Laser (IR-FEL) facility. The second stage is to build a synchrotron radiation facility named TURKAY, which is a third generation synchrotron radiation light source that aims to achieve a high brilliance photon beam from a low emittance electron beam at 3 GeV. The electron beam parameters are highly dependent on the magnetic lattice of the storage ring. In this paper a low emittance storage ring for TURKAY is proposed and the beam dynamic properties of the magnetic lattice are investigated. Supported by Turkish Republic Ministry of Development (DPT2006K120470)

Analytic model for ring pattern formation by bacterial swarmers

NASA Astrophysics Data System (ADS)

Arouh, Scott

2001-03-01

We analyze a model proposed by Medvedev, Kaper, and Kopell (the MKK model) for ring formation in two-dimensional bacterial colonies of Proteus mirabilis. We correct the model to formally include a feature crucial of the ring generation mechanism: a bacterial density threshold to the nonlinear diffusivity of the MKK model. We numerically integrate the model equations, and observe the logarithmic profiles of the bacterial densities near the front. These lead us to define a consolidation front distinct from the colony radius. We find that this consolidation front propagates outward toward the colony radius with a nearly constant velocity. We then implement the corrected MKK equations in two dimensions and compare our results with biological experiment. Our numerical results indicate that the two-dimensional corrected MKK model yields smooth (rather than branched) rings, and that colliding colonies merge if grown in phase but not if grown out of phase. We also introduce a model, based on coupling the MKK model to a nutrient field, for simulating experimentally observed branched rings.

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in 3He-B.

PubMed

Fisher, Shaun Neil; Jackson, Martin James; Sergeev, Yuri A; Tsepelin, Viktor

2014-03-25

Andreev reflection of quasiparticle excitations provides a sensitive and passive probe of flow in superfluid (3)He-B. It is particularly useful for studying complex flows generated by vortex rings and vortex tangles (quantum turbulence). We describe the reflection process and discuss the results of numerical simulations of Andreev reflection from vortex rings and from quantum turbulence. We present measurements of vortices generated by a vibrating grid resonator at very low temperatures. The Andreev reflection is measured using an array of vibrating wire sensors. At low grid velocities, ballistic vortex rings are produced. At higher grid velocities, the rings collide and reconnect to produce quantum turbulence. We discuss spatial correlations of the fluctuating vortex signals measured by the different sensor wires. These reveal detailed information about the formation of quantum turbulence and about the underlying vortex dynamics.

Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in 3He-B

PubMed Central

Fisher, Shaun Neil; Jackson, Martin James; Sergeev, Yuri A.; Tsepelin, Viktor

2014-01-01

Andreev reflection of quasiparticle excitations provides a sensitive and passive probe of flow in superfluid 3He-B. It is particularly useful for studying complex flows generated by vortex rings and vortex tangles (quantum turbulence). We describe the reflection process and discuss the results of numerical simulations of Andreev reflection from vortex rings and from quantum turbulence. We present measurements of vortices generated by a vibrating grid resonator at very low temperatures. The Andreev reflection is measured using an array of vibrating wire sensors. At low grid velocities, ballistic vortex rings are produced. At higher grid velocities, the rings collide and reconnect to produce quantum turbulence. We discuss spatial correlations of the fluctuating vortex signals measured by the different sensor wires. These reveal detailed information about the formation of quantum turbulence and about the underlying vortex dynamics. PMID:24704872

PEGASYS---A proposed internal target facility for the PEP storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Biber, K.

A proposal for an integral gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable, luminosity (L = 10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/) and energy (E/sub e/ less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 14 refs., 7 figs.

The KACST Heavy-Ion Electrostatic Storage Ring

NASA Astrophysics Data System (ADS)

Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.; Papash, A. I.; Welsch, C. P.

2011-10-01

A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The development of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.

The Shapers

NASA Image and Video Library

2015-01-26

Two masters of their craft are caught at work shaping Saturn's rings. Pandora (upper right) sculpts the F ring, as does nearby Prometheus (not seen in this image). Meanwhile, Daphnis is busy holding open the Keeler gap (bottom center), its presence revealed here by the waves it raises on the gap's edge. The faint moon is located where the inner and outer waves appear to meet. Also captured in this image, shining through the F ring above the image center, is a single star. Although gravity is by its very nature an attractive force, moons can interact with ring particles in such a way that they effectively push ring particles away from themselves. Ring particles experience tiny gravitational "kicks" from these moons and subsequently collide with other ring particles, losing orbital momentum. The net effect is for moons like Pandora (50 miles or 81 kilometers across) and Daphnis (5 miles or 8 kilometers across) to push ring edges away from themselves. The Keeler gap is the result of just such an interaction. This view looks toward the unilluminated side of the rings from about 50 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 30, 2013. http://photojournal.jpl.nasa.gov/catalog/PIA18298

BEAM DIAGNOSTICS USING BPM SIGNALS FROM INJECTED AND STORED BEAMS IN A STORAGE RING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, G.M.; Shaftan; T.

2011-03-28

Many modern light sources are operating in top-off injection mode or are being upgraded to top-off injection mode. The storage ring always has the stored beam and injected beam for top-off injection mode. So the BPM data is the mixture of both beam positions and the injected beam position cannot be measured directly. We propose to use dedicated wide band BPM electronics in the NSLS II storage ring to retrieve the injected beam trajectory with the singular value decomposition (SVD) method. The beam position monitor (BPM) has the capability to measure bunch-by-bunch beam position. Similar electronics can be used tomore » measure the bunch-by-bunch beam current which is necessary to get the injection beam position. The measurement precision of current needs to be evaluated since button BPM sum signal has position dependence. The injected beam trajectory can be measured and monitored all the time without dumping the stored beam. We can adjust and optimize the injected beam trajectory to maximize the injection efficiency. We can also measure the storage ring acceptance by mapping the injected beam trajectory.« less

First storage of ion beams in the Double Electrostatic Ion-Ring Experiment: DESIREE.

PubMed

Schmidt, H T; Thomas, R D; Gatchell, M; Rosén, S; Reinhed, P; Löfgren, P; Brännholm, L; Blom, M; Björkhage, M; Bäckström, E; Alexander, J D; Leontein, S; Hanstorp, D; Zettergren, H; Liljeby, L; Källberg, A; Simonsson, A; Hellberg, F; Mannervik, S; Larsson, M; Geppert, W D; Rensfelt, K G; Danared, H; Paál, A; Masuda, M; Halldén, P; Andler, G; Stockett, M H; Chen, T; Källersjö, G; Weimer, J; Hansen, K; Hartman, H; Cederquist, H

2013-05-01

We report on the first storage of ion beams in the Double ElectroStatic Ion Ring ExpEriment, DESIREE, at Stockholm University. We have produced beams of atomic carbon anions and small carbon anion molecules (C(n)(-), n = 1, 2, 3, 4) in a sputter ion source. The ion beams were accelerated to 10 keV kinetic energy and stored in an electrostatic ion storage ring enclosed in a vacuum chamber at 13 K. For 10 keV C2 (-) molecular anions we measure the residual-gas limited beam storage lifetime to be 448 s ± 18 s with two independent detector systems. Using the measured storage lifetimes we estimate that the residual gas pressure is in the 10(-14) mbar range. When high current ion beams are injected, the number of stored particles does not follow a single exponential decay law as would be expected for stored particles lost solely due to electron detachment in collision with the residual-gas. Instead, we observe a faster initial decay rate, which we ascribe to the effect of the space charge of the ion beam on the storage capacity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amerio, S.; Behari, S.; Boyd, J.

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and D0 experiments each have approximately 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 and beyond. To achieve this goal, we have implemented a system that utilizes virtualization, automated validation, and migration to new standards inmore » both software and data storage technology and leverages resources available from currently-running experiments at Fermilab. Lastly, these efforts have also provided useful lessons in ensuring long-term data access for numerous experiments, and enable high-quality scientific output for years to come.« less

Data preservation at the Fermilab Tevatron

NASA Astrophysics Data System (ADS)

Amerio, S.; Behari, S.; Boyd, J.; Brochmann, M.; Culbertson, R.; Diesburg, M.; Freeman, J.; Garren, L.; Greenlee, H.; Herner, K.; Illingworth, R.; Jayatilaka, B.; Jonckheere, A.; Li, Q.; Naymola, S.; Oleynik, G.; Sakumoto, W.; Varnes, E.; Vellidis, C.; Watts, G.; White, S.

2017-04-01

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and D0 experiments each have approximately 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 and beyond. To achieve this goal, we have implemented a system that utilizes virtualization, automated validation, and migration to new standards in both software and data storage technology and leverages resources available from currently-running experiments at Fermilab. These efforts have also provided useful lessons in ensuring long-term data access for numerous experiments, and enable high-quality scientific output for years to come.

SSC spool piece design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, D.; Costin, K.; Hutton, D.

1991-03-01

The spool piece design for the standard arc half-cell of the Superconducting Super Collider collider ring is an electromechanical system which performs a variety of tasks. The components provide conditioning and control of the cryogenics and electrical bus routing and protection; they also accommodate the beam position monitor and corrector magnet families, vacuum separation, and connection points for control and instrumentation. The design uses unique locations for each component, mixing form and function in a limited amount of allocated length in the standard 90 m half-cell. This paper describes the purpose and positioning of the various components and the assemblymore » sequence required to achieve these space constraints. 5 refs., 6 figs., 3 tabs.« less

Modular focusing ring imaging Cherenkov detector for electron–ion collider experiments

DOE PAGES

Wong, C. P.; Alfred, M.; Allison, L.; ...

2017-07-16

Here, a powerful new electron–ioncollider (EIC) has been recommended in the 2015 Long Range Plan for Nuclear Science for probing the partonic structure inside nucleons and nuclei with unprecedented precision and versatility. EIC detectors are currently under development, all of which require hadron identification over a broad kinematic range. A prototype ring imaging Cherenkov detector has been developed for hadron identification in the momentum range from 3 GeV/c to 10 GeV/c. The key feature of this new detector is a compact and modular design, achieved by using aerogel as radiator and a Fresnel lens for ring focusing. In this paper,more » the results from a beam test of a prototype device at Fermilab are reported.« less

High Resolution BPM Upgrade for the ATF Damping Ring at KEK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddy, N.; Briegel, C.; Fellenz, B.

2011-08-17

A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R&D effort. The upgrade consists of a high resolution, high reproducibility read-out system, based on analog and digital down-conversion techniques, digital signal processing, and also implements a new automatic gain error correction schema. The technical concept and realization as well as results of beam studies are presented. The next generation of linear colliders require ultra-low vertical emittance of <2 pm-rad. The damping ring at the KEK Accelerator Test Facilitymore » (ATF) is designed to demonstrate this mission critical goal. A high resolution beam position monitor (BPM) system for the damping ring is one of the key tools for realizing this goal. The BPM system needs to provide two distnict measurements. First, a very high resolution ({approx}100-200nm) closed-orbit measurement which is averaged over many turns and realized with narrowband filter techniques - 'narrowband mode'. This is needed to monitor and steer the beam along an optimum orbit and to facilitate beam-based alignment to minimize non-linear field effects. Second, is the ability to make turn by turn (TBT) measurements to support optics studies and corrections necessary to achieve the design performance. As the TBT measurement necessitates a wider bandwidth, it is often referred to as 'wideband mode'. The BPM upgrade was initiated as a KEK/SLAC/FNAL collaboration in the frame of the Global Design Initiative of the International Linear Collider. The project was realized and completed using Japan-US funds with Fermilab as the core partner.« less

Preliminary study of injection transients in the TPS storage ring

NASA Astrophysics Data System (ADS)

Chen, C. H.; Liu, Y. C.; Y Chen, J.; Chiu, M. S.; Tseng, F. H.; Fann, S.; Liang, C. C.; Huang, C. S.; Y Lee, T.; Y Chen, B.; Tsai, H. J.; Luo, G. H.; Kuo, C. C.

2017-07-01

An optimized injection efficiency is related to a perfect match between the pulsed magnetic fields in the storage ring and transfer line extraction in the TPS. However, misalignment errors, hardware output errors and leakage fields are unavoidable. We study the influence of injection transients on the stored TPS beam and discuss solutions to compensate these. Related simulations and measurements will be presented.

Vacuum system for room temperature X-ray lithography source (XLS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuchman, J.C.

1988-09-30

A prototype room-temperature X-Ray Lithography Source (XLS)was proposed to be built at Brookhaven National Laboratory as part of a technology-transfer- to-American-industry program. The overall machine comprises a full energy linac, a 170 meter long transport line, and a 39 meter circumference storage ring. The scope of this paper will be limited to describing the storage ring vacuum system. (AIP)

Vacuum system for room temperature X-ray lithography source (XLS)

NASA Astrophysics Data System (ADS)

Schuchman, J. C.

1988-09-01

A prototype room-temperature X-Ray Lithography Source (XLS)was proposed to be built at Brookhaven National Laboratory as part of a technology-transfer- to-American-industry program. The overall machine comprises a full energy linac, a 170 meter long transport line, and a 39 meter circumference storage ring. The scope of this paper will be limited to describing the storage ring vacuum system. (AIP)

Generalized Stability Conditions for an Ultra-Low Energy Electrostatic Charged Particle Storage Ring

NASA Astrophysics Data System (ADS)

Sullivan, Michael

A low energy (~50 eV) electrostatic storage ring has been constructed that can store a recirculating bunch of either electrons or ions. The charged particle bunch 'orbits' within an apparatus consisting of four lenses and two hemispherical deflector analysers, arranged in a 'race-track' configuration of length 64.1 cm. A theoretical study, using transfer matrices from charged particle optics for a 'symmetric' configuration of lens potentials, has been previously completed by Hammond et al. [New J. Phys. 11 (2009) 043033]. That approach was capable of predicting modes of storage which appeared as a resonant-like pattern. An 'asymmetric' configuration, new in this work and extending the previous study to apply to a more general case, has been completed and will be presented alongside experimental results. The level of agreement between the theoretical and experimental results is found to be excellent, and the robustness of the matrix formalism has eliminated the need to rely on computer simulation to achieve storage. This asymmetric arrangement of the lenses allows for greater flexibility in the operation of the ring, creating the potential for a more diverse range of applications and potentially aid in the design of future rings. Several spectra for both electrons and positive ions are presented to provide an indication as to how the charged particle bunch evolves as more orbits are completed. The number of counts inevitably decreases as a function of orbit number due to loss mechanisms. Enhanced measurement techniques, as well as the matrix theory, have made storage of the bunch for over a hundred orbits routine, corresponding to over 65 m travelled, and this is observed directly from the spectra. The application of the storage ring as a multi-pass time-of-flight mass spectrometer has been studied. The isotopes of krypton and xenon have been made to completely separate from one another out of a single pulse of ions. This is observed to occur after ~15 orbits of the ring, roughly 10 m of distance. Initial results have indicated that the mass resolution is approximately 5000. Limitations and potential improvements to the mass resolution are presented.

Measurement of Systematic Error Effects for a Sensitive Storage Ring EDM Polarimeter

NASA Astrophysics Data System (ADS)

Imig, Astrid; Stephenson, Edward

2009-10-01

The Storage Ring EDM Collaboration was using the Cooler Synchrotron (COSY) and the EDDA detector at the Forschungszentrum J"ulich to explore systematic errors in very sensitive storage-ring polarization measurements. Polarized deuterons of 235 MeV were used. The analyzer target was a block of 17 mm thick carbon placed close to the beam so that white noise applied to upstream electrostatic plates increases the vertical phase space of the beam, allowing deuterons to strike the front face of the block. For a detector acceptance that covers laboratory angles larger than 9 ^o, the efficiency for particles to scatter into the polarimeter detectors was about 0.1% (all directions) and the vector analyzing power was about 0.2. Measurements were made of the sensitivity of the polarization measurement to beam position and angle. Both vector and tensor asymmetries were measured using beams with both vector and tensor polarization. Effects were seen that depend upon both the beam geometry and the data rate in the detectors.

Feasibility of a ring FEL at low emittance storage rings

NASA Astrophysics Data System (ADS)

Agapov, I.

2015-09-01

A scheme for generating coherent radiation at latest generation low emittance storage rings such as PETRA III at DESY (Balewski et al., 2004 [1]) is proposed. The scheme is based on focusing and subsequent defocusing of the electron beam in the longitudinal phase space at the undulator location. The expected performance characteristics are estimated for radiation in the wavelength range of 500-1500 eV. It is shown that the average brightness is increased by several orders of magnitude compared to spontaneous undulator radiation, which can open new perspectives for photon-hungry soft X-ray spectroscopy techniques.

PEGASYS: A proposed internal target-spectrometer facility for the PEP storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Bibber, K.

A proposal for an internal gas-jet target and forward spectrometer for the PEP storage ring is described. The beam structure, allowable luminosity (L=10/sup 33/ cm/sup /minus/2/s/sup /minus/1/ for H/sub 2/, D/sub 2/ decreasing as Z/sup /minus/1.75/ for nuclear targets) and energy (E/sub e/less than or equal to 15 GeV) make the ring ideal for multiparticle coincidence studies in the scaling regime, and where perturbative QCD may be an apt description of some exclusive and semi-inclusive reactions. 17 refs., 5 figs.

Future Synchrotron Light Sources Based on Ultimate Storage Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Yunhai; /SLAC

2012-04-09

The main purpose of this talk is to describe how far one might push the state of the art in storage ring design. The talk will start with an overview of the latest developments and advances in the design of synchrotron light sources based on the concept of an 'ultimate' storage ring. The review will establish how bright a ring based light source might be, where the frontier of technological challenges are, and what the limits of accelerator physics are. Emphasis will be given to possible improvements in accelerator design and developments in technology toward the goal of achieving anmore » ultimate storage ring. An ultimate storage ring (USR), defined as an electron ring-based light source having an emittance in both transverse planes at the diffraction limit for the range of X-ray wavelengths of interest for a scientific community, would provide very high brightness photons having high transverse coherence that would extend the capabilities of X-ray imaging and probe techniques beyond today's performance. It would be a cost-effective, high-coherence 4th generation light source, competitive with one based on energy recovery linac (ERL) technology, serving a large number of users studying material, chemical, and biological sciences. Furthermore, because of the experience accumulated over many decades of ring operation, it would have the great advantage of stability and reliability. In this paper we consider the design of an USR having 10-pm-rad emittance. It is a tremendous challenge to design a storage ring having such an extremely low emittance, a factor of 100 smaller than those in existing light sources, especially such that it has adequate dynamic aperture and beam lifetime. In many ultra-low emittance designs, the injection acceptances are not large enough for accumulation of the electron beam, necessitating on-axis injection where stored electron bunches are completely replaced with newly injected ones. Recently, starting with the MAX-IV 7-bend achromatic cell, we have made significant progress with the design of PEP-X, a USR that would inhabit the decommissioned PEP-II tunnel at SLAC. The enlargement of the dynamic aperture is largely a result of the cancellations of the 4th-order resonances in the 3rd-order achromats and the effective use of lattice optimization programs. In this paper, we will show those cancellations of the 4th-order resonances using an analytical approach based on the exponential Lie operators and the Poisson brackets. Wherever possible, our analytical results will be compared with their numerical counterparts. Using the derived formulae, we will construct 4th-order geometric achromats and use them as modules for the lattice of the PEP-X USR, noting that only geometric terms are canceled to the 4th order.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, S.; Picasso, E.

This year the LEP (Large Electron-Positron) is expected to generate about a million more Z{sup 0}'s. This abundance of data will enable physicists to investigate rare decay modes, determine the precise mass and lifetime of the Z{sup 0}, study the processes underlying the production of hadrons (particles made up of quarks) and probe subtle aspects of the prevailing theory. Equally important, experiments at the LEP will try to discover new states of matter--in particular, the Higgs boson and perhaps also the top quark. Both of these massive particles are predicted by theory but have yet to be observed. Experimenters willmore » also be searching for phenomena that are not predicted by existing theories. The LEP Collider is destined to be the preeminent tool for particle physics in the next decade. Its spectacular performance to data is a tribute to the ingenuity and determined effort of hundreds of technicians, engineers and scientists from more than 25 nations who collaborated on the LEP and its detectors. With an average diameter of 8,486 meters and a beam-collision energy of 100 billion electron volts, or gigaelectron volts (GeV), the LEP is the largest and most powerful electron-positron storage ring ever built. Because the electrons and positrons have the same energy and are colliding head-on, the total energy available in the center of mass of the system is simply twice the beam energy. The LEP, with present collision energies of up to 110 GeV, generates Z{sup 0} particles. It will eventually be upgraded to 200 GeV and generate particles known as the W{sup +} and W{sup {minus}}. Each of these three particles weighs about 90 GeV, or about 100 times the mass of the proton.« less

Test of Relativistic Gravity for Propulsion at the Large Hadron Collider

NASA Astrophysics Data System (ADS)

Felber, Franklin

2010-01-01

A design is presented of a laboratory experiment that could test the suitability of relativistic gravity for propulsion of spacecraft to relativistic speeds. An exact time-dependent solution of Einstein's gravitational field equation confirms that even the weak field of a mass moving at relativistic speeds could serve as a driver to accelerate a much lighter payload from rest to a good fraction of the speed of light. The time-dependent field of ultrarelativistic particles in a collider ring is calculated. An experiment is proposed as the first test of the predictions of general relativity in the ultrarelativistic limit by measuring the repulsive gravitational field of bunches of protons in the Large Hadron Collider (LHC). The estimated `antigravity beam' signal strength at a resonant detector of each proton bunch is 3 nm/s2 for 2 ns during each revolution of the LHC. This experiment can be performed off-line, without interfering with the normal operations of the LHC.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mcwilliams, A. J.; Daugherty, W. L.; Skidmore, T. E.

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report for Packaging (SARP) requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to providemore » a technical basis to extend that period. This report describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both GLT and GLT-S compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior. The CSR behavior of O-rings was evaluated at temperatures from 175 to 400 °F. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 156 °F). The predictive model developed from the CSR data conservatively indicates a service life of approximately 37 years for Viton GLT O-rings at the maximum effective service temperature of 156 °F. The estimated service life for Viton GLT-S O-rings is significantly longer.« less

The KACST Heavy-Ion Electrostatic Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.

2011-10-27

A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The developmentmore » of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, J.; Herner, K.; Jayatilaka, B.

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and DO experiments each have nearly 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 or beyond. To achieve this, we are implementing a system that utilizes virtualization, automated validation, and migration to new standards in bothmore » software and data storage technology as well as leveraging resources available from currently-running experiments at Fermilab. Furthermore, these efforts will provide useful lessons in ensuring long-term data access for numerous experiments throughout high-energy physics, and provide a roadmap for high-quality scientific output for years to come.« less

Data preservation at the Fermilab Tevatron

DOE PAGES

Amerio, S.; Behari, S.; Boyd, J.; ...

2017-01-22

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and D0 experiments each have approximately 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 and beyond. To achieve this goal, we have implemented a system that utilizes virtualization, automated validation, and migration to new standards inmore » both software and data storage technology and leverages resources available from currently-running experiments at Fermilab. Lastly, these efforts have also provided useful lessons in ensuring long-term data access for numerous experiments, and enable high-quality scientific output for years to come.« less

Data preservation at the Fermilab Tevatron

DOE PAGES

Boyd, J.; Herner, K.; Jayatilaka, B.; ...

2015-12-23

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and DO experiments each have nearly 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 or beyond. To achieve this, we are implementing a system that utilizes virtualization, automated validation, and migration to new standards in bothmore » software and data storage technology as well as leveraging resources available from currently-running experiments at Fermilab. Furthermore, these efforts will provide useful lessons in ensuring long-term data access for numerous experiments throughout high-energy physics, and provide a roadmap for high-quality scientific output for years to come.« less

Data preservation at the Fermilab Tevatron

NASA Astrophysics Data System (ADS)

Boyd, J.; Herner, K.; Jayatilaka, B.; Roser, R.; Sakumoto, W.

2015-12-01

The Fermilab Tevatron collider's data-taking run ended in September 2011, yielding a dataset with rich scientific potential. The CDF and DO experiments each have nearly 9 PB of collider and simulated data stored on tape. A large computing infrastructure consisting of tape storage, disk cache, and distributed grid computing for physics analysis with the Tevatron data is present at Fermilab. The Fermilab Run II data preservation project intends to keep this analysis capability sustained through the year 2020 or beyond. To achieve this, we are implementing a system that utilizes virtualization, automated validation, and migration to new standards in both software and data storage technology as well as leveraging resources available from currently-running experiments at Fermilab. These efforts will provide useful lessons in ensuring long-term data access for numerous experiments throughout high-energy physics, and provide a roadmap for high-quality scientific output for years to come.

Experimental Evidence for the Los Alamos Proton Storage Ring Beam Instability

NASA Astrophysics Data System (ADS)

Plum, M.; Fitzgerald, D. H.; Macek, R.; Sander, O.; Thiessen, H. A.; Wang, T. S.; Wilkinson, C.

1997-05-01

Although the exact instability mechanism at the Proton Storage Ring (PSR) has not yet been conclusively identified, the evidence gathered to date is consistent with an e-p instability. We have recently acquired new data which shows that clearing electrodes significantly affect the instability threshold. A set of comprehensive measurements is also planned for the first months of 1997. In this paper we will present our latest data.

Fundamentals of Coherent Synchrotron Radiation in Storage Rings

NASA Astrophysics Data System (ADS)

Sannibale, F.; Byrd, J. M.; Loftsdottir, A.; Martin, M. C.; Venturini, M.

2004-05-01

We present the fundamental concepts for producing stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The analysis includes distortion of bunch shape from the synchrotron radiation (SR), enhancing higher frequency coherent emission and limits to stable emission due to a microbunching instability excited by the SR. We use these concepts to optimize the performance of a source for CSR emission.

Design and performance of the readout electronics chain of the Delphi Forward Ring Imaging Cherenkov Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dam, P.; Nielsen, B.S.; Formenti, F.

1992-10-01

In this paper the Front End Readout electronics chain of the Forward Ring Imaging CHerenkov (FRICH) Detector used at the Delphi experiment of the Large Electron Positron (LEP) collider is presented. The system incorporates a wide band low noise preamplifier, mounted in the proximity of the MultiWire Proportional Chamber, an Amplifying-Discriminating-Multiple-xing FASTBUS unit for further signal amplification, discrimination and channel reduction and a LEP Time Digitizer FASTBUS unit for time digitization. The paper gives a general view of the detector and its electronics with particular emphasis on the novel characteristics and capabilities of the system.

Something old, something new: Why models need a multi-pool representation of storage reserves

NASA Astrophysics Data System (ADS)

Richardson, Andrew; Carbone, Mariah

2015-04-01

We know surprisingly little about processes regulating the allocation of photosynthetic assimilates to growth, storage, and other metabolic functions. Storage of nonstructural carbon (NSC, principally sugars and starch) is critically important for woody plants, because these reserves enable sessile, long-lived organisms to tolerate biotic and abiotic stress, including pests, disturbance, and drought. But, critical questions about the size and turnover of these reserves remain unanswered. Labeling studies have generally shown rapid use of new (labeled) NSC and inferred fast mixing between old and new NSC, both of which suggest quick turnover of storage reserves. However, recent studies have shown that some of the reserves stored in stem and root tissue are not only a decade old, but also still available to support new tissue growth following catastrophic disturbance. We characterized the distribution of NSC in the stemwood, branches, and roots of two temperate trees, and we used the continuous label offered by the radiocarbon (14C) bomb spike to estimate the mean age of NSC in different tissues of two temperate trees. NSC in branches and outermost stemwood growth rings had the 14C signature of the current growing season. However, NSC in older above- and below-ground tissues was enriched in 14C, indicating that it was produced from older assimilates. Radial patterns of 14C in stemwood NSC showed strong mixing of NSC across the youngest growth rings, with limited "mixing in" of younger NSC to older rings. Sugars in the outermost 5 growth rings, accounting for two-thirds of the stemwood pool, had a mean age < 1 y, whereas sugars in older growth rings had a mean age > 5 y. Thus, there is not a single, well-mixed "storage pool," and indeed "young" and "old" storage compounds appear to be physically isolated from each other. We will discuss the implications of these results for improving model representation of NSC storage and consumption by forest trees. We will suggest that there are conceptual similarities between modeling NSC pools and modeling soil C pools. We will propose future directions for modeling NSCs and also identify key questions that still need to be answered with new experimental work.

4-twist helix snake to maintain polarization in multi-GeV proton rings

DOE PAGES

Antoulinakis, F.; Chen, Y.; Dutton, A.; ...

2017-09-27

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120 GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120 GeV/c range. We foundmore » that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. Here, this snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.« less

4-twist helix snake to maintain polarization in multi-GeV proton rings

NASA Astrophysics Data System (ADS)

Antoulinakis, F.; Chen, Y.; Dutton, A.; Rossi De La Fuente, E.; Haupert, S.; Ljungman, E. A.; Myers, P. D.; Thompson, J. K.; Tai, A.; Aidala, C. A.; Courant, E. D.; Krisch, A. D.; Leonova, M. A.; Lorenzon, W.; Raymond, R. S.; Sivers, D. W.; Wong, V. K.; Yang, T.; Derbenev, Y. S.; Morozov, V. S.; Kondratenko, A. M.

2017-09-01

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven's 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab's 120 GeV /c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9 - 120 GeV /c range. We found that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. This snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.

4-twist helix snake to maintain polarization in multi-GeV proton rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antoulinakis, F.; Chen, Y.; Dutton, A.

Solenoid Siberian snakes have successfully maintained polarization in particle rings below 1 GeV, but never in multi-GeV rings, because the spin rotation by a solenoid is inversely proportional to the beam momentum. High energy rings, such as Brookhaven’s 255 GeV Relativistic Heavy Ion Collider (RHIC), use only odd multiples of pairs of transverse B-field Siberian snakes directly opposite each other. When it became impractical to use a pair of Siberian Snakes in Fermilab’s 120 GeV/c Main Injector, we searched for a new type of single Siberian snake that could overcome all depolarizing resonances in the 8.9–120 GeV/c range. We foundmore » that a snake made of one 4-twist helix and 2 dipoles could maintain the polarization. Here, this snake design could solve the long-standing problem of significant polarization loss during acceleration of polarized protons from a few GeV to tens of GeV, such as in the AGS, before injecting them into multi-hundred GeV rings, such as RHIC.« less

Selected topics in particle accelerators: Proceedings of the CAP meetings. Volume 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsa, Z.

1995-10-01

This Report includes copies of transparencies and notes from the presentations made at the Center for Accelerator Physics at Brookhaven National Laboratory Editing and changes to the authors` contributions in this Report were made only to fulfill the publication requirements. This volume includes notes and transparencies on nine presentations: ``The Energy Exchange and Efficiency Consideration in Klystrons``, ``Some Properties of Microwave RF Sources for Future Colliders + Overview of Microwave Generation Activity at the University of Maryland``, ``Field Quality Improvements in Superconducting Magnets for RHIC``, ``Hadronic B-Physics``, ``Spiking Pulses from Free Electron Lasers: Observations and Computational Models``, ``Crystalline Beams inmore » Circular Accelerators``, ``Accumulator Ring for AGS & Recent AGS Performance``, ``RHIC Project Machine Status``, and ``Gamma-Gamma Colliders.``« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex

Baseline design of the JLEIC booster synchrotron is presented. Its aim is to inject and accumulate heavy ions and protons at 285 MeV, to accelerate them to about 7 GeV, and finally to extract the beam into the ion collider ring. The Figure-8 ring features two 2600 achromatic arcs configured with negative momentum compaction optics, designed to avoid transition crossing for all ion species during the course of acceleration. The lattice also features a specialized high dispersion injection insert optimized to facilitate the transverse phase-space painting in both planes for multi-turn ion injection. Furthermore, the lattice has been optimized tomore » ease chromaticity correction with two families of sextupoles in each plane. The booster ring is configured with super-ferric, 3 Tesla bends. We are presently launching optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime.« less

Evidence for an oscillating soliton/vortex ring by density engineering of a Bose-Einstein condensate

NASA Astrophysics Data System (ADS)

Shomroni, I.; Lahoud, E.; Levy, S.; Steinhauer, J.

2009-03-01

When two Bose-Einstein condensates collide with high collisional energy, the celebrated matter-wave interference pattern appears. For lower collisional energies, the repulsive interaction energy becomes significant, and the interference pattern evolves into an array of grey solitons. But the lowest collisional energies, producing a single pair of solitons, have not been probed so far. Here, we report on experiments using density engineering on the healing length scale to produce such a pair of solitons. We see evidence that the solitons evolve periodically between vortex rings and solitons. The stable, periodic evolution is in sharp contrast to the behaviour seen in previous experiments in which the solitons decay irreversibly into vortex rings through the so-called snake instability. The evolution can be understood in terms of conservation of mass and energy in a narrow condensate.

High Pressure Gas Filled RF Cavity Beam Test at the Fermilab MuCool Test Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freemire, Ben

2013-05-01

The high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators. In the realm of leptons, only electron colliders have been built to date. Compared to hadrons, electrons lose a large amount of energy when accelerated in a ring through synchrotron radiation. A solution to this problem is to build long, straight accelerators for electrons, which has been done with great success. With a new generation of lepton colliders being conceived, building longer, more powerful accelerators is not the most enticing option. Muons have been proposed as an alternativemore » particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a much smaller energy range than a comparable electron collider. This allows a circular collider to be built with higher attainable energy than any present electron collider. As part of the accelerator, but separate from the collider, it would also be possible to allow the muons to decay to study neutrinos. The possibility of a high energy, high luminosity muon collider and an abundant, precise source of neutrinos is an attractive one. The technological challenges of building a muon accelerator are many and diverse. Because the muon is an unstable particle, a muon beam must be cooled and accelerated to the desired energy within a short amount of time. This requirement places strict requisites on the type of acceleration and focusing that can be used. Muons are generated as tertiary beams with a huge phase space, so strong magnetic fields are required to capture and focus them. Radio frequency (RF) cavities are needed to capture, bunch and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary for capture and focusing.« less

The Potential-Well Distortion Effect and Coherent Instabilities of Electron Bunches in Storage Rings

NASA Astrophysics Data System (ADS)

Korchuganov, V. N.; Smygacheva, A. S.; Fomin, E. A.

2018-05-01

The effect of electromagnetic interaction between electron bunches and the vacuum chamber of a storage ring on the longitudinal motion of bunches is studied. Specifically, the potential-well distortion effect and the so-called coherent instabilities of coupled bunches are considered. An approximate analytical solution for the frequencies of incoherent oscillations of bunches distributed arbitrarily within the ring is obtained for a distorted potential well. A new approach to determining frequencies of coherent oscillations and an approximate analytical relation for estimating the stability of a system of bunches as a function of their distribution in the accelerator orbit are presented.

Observation of e+e-→ηJ/ψ at center-of-mass energy s=4.009GeV

NASA Astrophysics Data System (ADS)

Ablikim, M.; Achasov, M. N.; Ambrose, D. J.; An, F. F.; An, Q.; An, Z. H.; Bai, J. Z.; Ban, Y.; Becker, J.; Bennett, J. V.; Bertani, M.; Bian, J. M.; Boger, E.; Bondarenko, O.; Boyko, I.; Briere, R. A.; Bytev, V.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y. B.; Cheng, H. P.; Chu, Y. P.; Cronin-Hennessy, D.; Dai, H. L.; Dai, J. P.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; Ding, W. M.; Ding, Y.; Dong, L. Y.; Dong, M. Y.; Du, S. X.; Fang, J.; Fang, S. S.; Fava, L.; Feldbauer, F.; Feng, C. Q.; Ferroli, R. B.; Fu, C. D.; Fu, J. L.; Gao, Y.; Geng, C.; Goetzen, K.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, Y. P.; Han, Y. L.; Harris, F. A.; He, K. L.; He, M.; He, Z. Y.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Huang, G. M.; Huang, J. S.; Huang, X. T.; Huang, Y. P.; Hussain, T.; Ji, C. S.; Ji, Q.; Ji, X. B.; Ji, X. L.; Jiang, L. L.; Jiang, X. S.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jing, F. F.; Kalantar-Nayestanaki, N.; Kavatsyuk, M.; Kuehn, W.; Lai, W.; Lange, J. S.; Li, C. H.; Li, Cheng; Li, Cui; Li, D. M.; Li, F.; Li, G.; Li, H. B.; Li, J. C.; Li, K.; Li, Lei; Li, Q. J.; Li, S. L.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, X. R.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, X. T.; Liu, B. J.; Liu, C. L.; Liu, C. X.; Liu, C. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H.; Liu, H. B.; Liu, H. H.; Liu, H. M.; Liu, H. W.; Liu, J. P.; Liu, K. Y.; Liu, Kai; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, X. H.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqiang; Liu, Zhiqing; Loehner, H.; Lu, G. R.; Lu, H. J.; Lu, J. G.; Lu, Q. W.; Lu, X. R.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lv, M.; Ma, C. L.; Ma, F. C.; Ma, H. L.; Ma, Q. M.; Ma, S.; Ma, T.; Ma, X. Y.; Ma, Y.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mao, Y. J.; Mao, Z. P.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Morales, C. Morales; Motzko, C.; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nicholson, C.; Nikolaev, I. B.; Ning, Z.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Park, J. W.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Ping, J. L.; Ping, R. G.; Poling, R.; Prencipe, E.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, X. S.; Qin, Y.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Rong, G.; Ruan, X. D.; Sarantsev, A.; Schaefer, B. D.; Schulze, J.; Shao, M.; Shen, C. P.; Shen, X. Y.; Sheng, H. Y.; Shepherd, M. R.; Song, W. M.; Song, X. Y.; Spataro, S.; Spruck, B.; Sun, D. H.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Toth, D.; Ullrich, M.; Varner, G. S.; Wang, B.; Wang, B. Q.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, Q.; Wang, Q. J.; Wang, S. G.; Wang, X. L.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wei, D. H.; Weidenkaff, P.; Wen, Q. G.; Wen, S. P.; Werner, M.; Wiedner, U.; Wu, L. H.; Wu, N.; Wu, S. X.; Wu, W.; Wu, Z.; Xia, L. G.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, G. M.; Xu, H.; Xu, Q. J.; Xu, X. P.; Xu, Z. R.; Xue, F.; Xue, Z.; Yan, L.; Yan, W. B.; Yan, Y. H.; Yang, H. X.; Yang, Y.; Yang, Y. X.; Ye, H.; Ye, M.; Ye, M. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yu, S. P.; Yuan, C. Z.; Yuan, Y.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, S. H.; Zhang, X. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. S.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, H. S.; Zhao, J. W.; Zhao, K. X.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, X. H.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y. H.; Zhong, B.; Zhong, J.; Zhou, L.; Zhou, X. K.; Zhou, X. R.; Zhu, C.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, X. L.; Zhu, X. W.; Zhu, Y. C.; Zhu, Y. M.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.

2012-10-01

Using a 478pb-1 data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring at a center-of-mass energy of s=4.009GeV, the production of e+e-→ηJ/ψ is observed for the first time with a statistical significance of greater than 10σ. The Born cross section is measured to be (32.1±2.8±1.3)pb, where the first error is statistical and the second systematic. Assuming the ηJ/ψ signal is from a hadronic transition of the ψ(4040), the fractional transition rate is determined to be B(ψ(4040)→ηJ/ψ)=(5.2±0.5±0.2±0.5)×10-3, where the first, second, and third errors are statistical, systematic, and the uncertainty from the ψ(4040) resonant parameters, respectively. The production of e+e-→π0J/ψ is searched for, but no significant signal is observed, and B(ψ(4040)→π0J/ψ)<2.8×10-4 is obtained at the 90% confidence level.

Theoretical study of hydrogen storage in a truncated triangular pyramid molecule consisting of pyridine and benzene rings bridged by vinylene groups

NASA Astrophysics Data System (ADS)

Ishikawa, Shigeru; Nemoto, Tetsushi; Yamabe, Tokio

2018-06-01

Hydrogen storage in a truncated triangular pyramid molecule C33H21N3, which consists of three pyridine rings and one benzene ring bridged by six vinylene groups, is studied by quantum chemical methods. The molecule is derived by substituting three benzene rings in a truncated tetrahedron hydrocarbon C36H24 with pyridine rings. The optimized molecular structure under C 3v symmetry shows no imaginary vibrational modes at the B3LYP/cc-pVTZ level of theory. The hydrogen storage process is investigated based on the MP2/cc-pVTZ method. Like the structure before substitution, the C33H21N3 molecule has a cavity that stores a hydrogen molecule with a binding energy of - 140 meV. The Langmuir isotherm shows that this cavity can store hydrogen at higher temperatures and lower pressures than usual physisorption materials. The C33H21N3 molecule has a kinetic advantage over the C36H24 molecule because the former molecule has a lower barrier (+ 560 meV) for the hydrogen molecule entering the cavity compared with the latter molecule (+ 730 meV) owing to the lack of hydrogen atoms narrowing the opening.

Electron-cloud updated simulation results for the PSR, and recent results for the SNS

NASA Astrophysics Data System (ADS)

Pivi, M.; Furman, M. A.

2002-05-01

Recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source (SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR) at Los Alamos are presented in this paper. A refined model for the secondary emission process including the so called true secondary, rediffused and backscattered electrons has recently been included in the electron-cloud code.

Multi-objective dynamic aperture optimization for storage rings

DOE PAGES

Li, Yongjun; Yang, Lingyun

2016-11-30

We report an efficient dynamic aperture (DA) optimization approach using multiobjective genetic algorithm (MOGA), which is driven by nonlinear driving terms computation. It was found that having small low order driving terms is a necessary but insufficient condition of having a decent DA. Then direct DA tracking simulation is implemented among the last generation candidates to select the best solutions. The approach was demonstrated successfully in optimizing NSLS-II storage ring DA.

Towards a 4{sup th} generation storage ring at the Canadian Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dallin, Les; Wurtz, Ward

2016-07-27

Demands from beamline scientists for more brilliant sources of synchrotron radiation have resulted in the emergence of 4{sup th} generation (diffraction-limited) storage rings. The practical development of the multi-bend achromat (MBA) concept by MAX IV lab has spurred many synchrotron light sources around the world to develop similar machines. For existing facilities two options are available: upgrading existing machines or building a new structure. The Canadian Light Source (CLS) has explored both options. For a new low emittance source in the existing CLS tunnel a decrease in electron energy would be required. A machine similar to the ALS upgrade couldmore » be contemplated. To achieve low emittance at our present energy of 2.9 GeV a new storage ring is desirable. Several options have been investigated. These designs use extremely strong focusing magnets to achieve extremely low emittances in compact lattice achromats.« less

Preparing the MAX IV storage rings for timing-based experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stråhlman, C., E-mail: Christian.Strahlman@maxlab.lu.se; Olsson, T., E-mail: Teresia.Olsson@maxlab.lu.se; Leemann, S. C.

2016-07-27

Time-resolved experimental techniques are increasingly abundant at storage ring facilities. Recent developments in accelerator technology and beamline instrumentation allow for simultaneous operation of high-intensity and timing-based experiments. The MAX IV facility is a state-of-the-art synchrotron light source in Lund, Sweden, that will come into operation in 2016. As many storage ring facilities are pursuing upgrade programs employing strong-focusing multibend achromats and passive harmonic cavities (HCs) in high-current operation, it is of broad interest to study the accelerator and instrumentation developments required to enable timing-based experiments at such machines. In particular, the use of hybrid filling modes combined with pulse pickingmore » by resonant excitation or pseudo single bunch has shown promising results. These methods can be combined with novel beamline instrumentation, such as choppers and instrument gating. In this paper we discuss how these techniques can be implemented and employed at MAX IV.« less

Upgrading the Digital Electronics of the PEP-II Bunch Current Monitors at the Stanford Linear Accelerator Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kline, Josh; /SLAC

2006-08-28

The testing of the upgrade prototype for the bunch current monitors (BCMs) in the PEP-II storage rings at the Stanford Linear Accelerator Center (SLAC) is the topic of this paper. Bunch current monitors are used to measure the charge in the electron/positron bunches traveling in particle storage rings. The BCMs in the PEP-II storage rings need to be upgraded because components of the current system have failed and are known to be failure prone with age, and several of the integrated chips are no longer produced making repairs difficult if not impossible. The main upgrade is replacing twelve old (1995)more » field programmable gate arrays (FPGAs) with a single Virtex II FPGA. The prototype was tested using computer synthesis tools, a commercial signal generator, and a fast pulse generator.« less

A compact radiation source for digital subtractive angiography

NASA Astrophysics Data System (ADS)

Wiedemann, H.; Baltay, M.; Carr, R.; Hernandez, M.; Lavender, W.

1994-08-01

Beam requirements for 33 keV radiation used in digital subtraction angiography have been established through extended experimentation first at Stanford and later at the National Synchrotron Light Source in Brookhaven. So far research and development of this medical procedure to image coronary blood vessels have been undertaken on large high energy electron storage rings. With progress in this diagnostic procedure, it is interesting to look for an optimum concept for providing a 33 keV radiation source which would fit into the environment of a hospital. A variety of competing effects and technologies to produce 33 keV radiation are available, but none of these processes provides the combination of sufficient photon flux and monochromaticity except for synchrotron radiation from an electron storage ring. The conceptual design of a compact storage ring optimized to fit into a hospital environment and producing sufficient 33 keV radiation for digital subtraction radiography will be discussed.

X-ray nanoprobes and diffraction-limited storage rings: opportunities and challenges of fluorescence tomography of biological specimens

PubMed Central

de Jonge, Martin D.; Ryan, Christopher G.; Jacobsen, Chris J.

2014-01-01

X-ray nanoprobes require coherent illumination to achieve optic-limited resolution, and so will benefit directly from diffraction-limited storage rings. Here, the example of high-resolution X-ray fluorescence tomography is focused on as one of the most voracious demanders of coherent photons, since the detected signal is only a small fraction of the incident flux. Alternative schemes are considered for beam delivery, sample scanning and detectors. One must consider as well the steps before and after the X-ray experiment: sample preparation and examination conditions, and analysis complexity due to minimum dose requirements and self-absorption. By understanding the requirements and opportunities for nanoscale fluorescence tomography, one gains insight into the R&D challenges in optics and instrumentation needed to fully exploit the source advances that diffraction-limited storage rings offer. PMID:25177992

Modeling Systematic Error Effects for a Sensitive Storage Ring EDM Polarimeter

NASA Astrophysics Data System (ADS)

Stephenson, Edward; Imig, Astrid

2009-10-01

The Storage Ring EDM Collaboration has obtained a set of measurements detailing the sensitivity of a storage ring polarimeter for deuterons to small geometrical and rate changes. Various schemes, such as the calculation of the cross ratio [1], can cancel effects due to detector acceptance differences and luminosity differences for states of opposite polarization. Such schemes fail at second-order in the errors, becoming sensitive to geometrical changes, polarization magnitude differences between opposite polarization states, and changes to the detector response with changing data rates. An expansion of the polarimeter response in a Taylor series based on small errors about the polarimeter operating point can parametrize such effects, primarily in terms of the logarithmic derivatives of the cross section and analyzing power. A comparison will be made to measurements obtained with the EDDA detector at COSY-J"ulich. [4pt] [1] G.G. Ohlsen and P.W. Keaton, Jr., NIM 109, 41 (1973).

Symplectic orbit and spin tracking code for all-electric storage rings

NASA Astrophysics Data System (ADS)

Talman, Richard M.; Talman, John D.

2015-07-01

Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring "trap." At the "magic" kinetic energy of 232.792 MeV, proton spins are "frozen," for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10-29e -cm or greater will produce a statistically significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial "symplectification"). Any residual spurious damping or antidamping is sufficiently small to permit reliable tracking for the long times, such as the 1000 s assumed in estimating the achievable EDM precision. This paper documents in detail the theoretical formulation implemented in eteapot. An accompanying paper describes the practical application of the eteapot code in the Universal Accelerator Libraries (ual) environment to "resurrect," or reverse engineer, the "AGS-analog" all-electric ring built at Brookhaven National Laboratory in 1954. Of the (very few) all-electric rings ever commissioned, the AGS-analog ring is the only relativistic one and is the closest to what is needed for measuring proton (or, even more so, electron) EDM's. The companion paper also describes preliminary lattice studies for the planned proton EDM storage rings as well as testing the code for long time orbit and spin tracking.

Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape

PubMed Central

Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D.; Tardif, Jacques C.; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

2015-01-01

Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems. PMID:26528316

Capturing spiral radial growth of conifers using the superellipse to model tree-ring geometric shape.

PubMed

Shi, Pei-Jian; Huang, Jian-Guo; Hui, Cang; Grissino-Mayer, Henri D; Tardif, Jacques C; Zhai, Li-Hong; Wang, Fu-Sheng; Li, Bai-Lian

2015-01-01

Tree-rings are often assumed to approximate a circular shape when estimating forest productivity and carbon dynamics. However, tree rings are rarely, if ever, circular, thereby possibly resulting in under- or over-estimation in forest productivity and carbon sequestration. Given the crucial role played by tree ring data in assessing forest productivity and carbon storage within a context of global change, it is particularly important that mathematical models adequately render cross-sectional area increment derived from tree rings. We modeled the geometric shape of tree rings using the superellipse equation and checked its validation based on the theoretical simulation and six actual cross sections collected from three conifers. We found that the superellipse better describes the geometric shape of tree rings than the circle commonly used. We showed that a spiral growth trend exists on the radial section over time, which might be closely related to spiral grain along the longitudinal axis. The superellipse generally had higher accuracy than the circle in predicting the basal area increment, resulting in an improved estimate for the basal area. The superellipse may allow better assessing forest productivity and carbon storage in terrestrial forest ecosystems.

Inverse compton light source: a compact design proposal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deitrick, Kirsten Elizabeth

In the last decade, there has been an increasing demand for a compact Inverse Compton Light Source (ICLS) which is capable of producing high-quality X-rays by colliding an electron beam and a high-quality laser. It is only in recent years when both SRF and laser technology have advanced enough that compact sources can approach the quality found at large installations such as the Advanced Photon Source at Argonne National Laboratory. Previously, X-ray sources were either high flux and brilliance at a large facility or many orders of magnitude lesser when produced by a bremsstrahlung source. A recent compact source wasmore » constructed by Lyncean Technologies using a storage ring to produce the electron beam used to scatter the incident laser beam. By instead using a linear accelerator system for the electron beam, a significant increase in X-ray beam quality is possible, though even subsequent designs also featuring a storage ring offer improvement. Preceding the linear accelerator with an SRF reentrant gun allows for an extremely small transverse emittance, increasing the brilliance of the resulting X-ray source. In order to achieve sufficiently small emittances, optimization was done regarding both the geometry of the gun and the initial electron bunch distribution produced off the cathode. Using double-spoke SRF cavities to comprise the linear accelerator allows for an electron beam of reasonable size to be focused at the interaction point, while preserving the low emittance that was generated by the gun. An aggressive final focusing section following the electron beam's exit from the accelerator produces the small spot size at the interaction point which results in an X-ray beam of high flux and brilliance. Taking all of these advancements together, a world class compact X-ray source has been designed. It is anticipated that this source would far outperform the conventional bremsstrahlung and many other compact ICLSs, while coming closer to performing at the levels found at large facilities than ever before. The design process, including the development between subsequent iterations, is presented here in detail, with the simulation results for this groundbreaking X-ray source.« less

BEAM ON TARGET MODEL Produces All Gamma Ray Burst Phenomena Including Afterglow

NASA Astrophysics Data System (ADS)

Greyber, H.

2000-12-01

While one must applaud the splendid research by L. Piro et al and L. Amati et al reported in SCIENCE recently, one must question, as M. Rees and S. Woolsey have done, their conclusion that a ``supranova model" is the only explanation for these new X-ray observations. In fact L. Piro was quoted as saying, ``Our data helps rule out the scenario where two neutron stars or black holes collide. We think GRBs result from something similar to a supernova explosion, but much more powerful." A relatively unknown physical model for GRBs, Greyber's Beam On Target model (BOT), dating back to the first CGRO observations, can plausibly explain the iron emission lines observed for GRB991216, and also the mass of the dense medium within a light-day of the GRB being roughly equivalent to at least one-tenth solar mass, as well as the initial shedding of material followed by the GRB event. When a galaxy forms under gravitational collapse in the presence of a primordial magnetic field, Mestel and Strittmatter demonstrated that, for finite Ohmic diffusion, a growing equatorial current loop is formed. Even if this stable ``Storage Ring" has only 10exp-9 of the total energy released during a typical galaxy's formation, the relativistic beam can possess 10exp58 ergs. The GRB ``fireball" occurs when a target star races across the powerful beam, blowing off target material as a hot, rapidly expanding plasma cloud, simulating an explosion. Since currents in space are known to be sometimes filamentary, sharp millisecond spikes can be expected in some GRBs. Proton and alpha particle nuclear reactions produce a gamma ray beam. Beam particles impinging on denser cloud material create an electromagnetic shower, producing X-ray, optical and radio radiation. Since the Storage Ring has an intense magnetic field around it, synchrotron radiation is expected. The beam, striking a highly evolved massive target star, produces the iron emission lines. H. D. Greyber, in ``After the Dark Ages:When Galaxies Were Young", A.I.P. Confer. Proc. no.470, 388, (1999) L. Mestel & P. Strittmatter, Mon. Not. Royal Astron. Society, 137, 95, (1967)

Resonant structure of low-energy H3+ dissociative recombination

NASA Astrophysics Data System (ADS)

Petrignani, Annemieke; Altevogt, Simon; Berg, Max H.; Bing, Dennis; Grieser, Manfred; Hoffmann, Jens; Jordon-Thaden, Brandon; Krantz, Claude; Mendes, Mario B.; Novotný, Oldřich; Novotny, Steffen; Orlov, Dmitry A.; Repnow, Roland; Sorg, Tobias; Stützel, Julia; Wolf, Andreas; Buhr, Henrik; Kreckel, Holger; Kokoouline, Viatcheslav; Greene, Chris H.

2011-03-01

High-resolution dissociative recombination rate coefficients of rotationally cool and hot H3+ in the vibrational ground state have been measured with a 22-pole trap setup and a Penning ion source, respectively, at the ion storage-ring TSR. The experimental results are compared with theoretical calculations to explore the dependence of the rate coefficient on ion temperature and to study the contributions of different symmetries to probe the rich predicted resonance spectrum. The kinetic energy release was investigated by fragment imaging to derive internal temperatures of the stored parent ions under differing experimental conditions. A systematic experimental assessment of heating effects is performed which, together with a survey of other recent storage-ring data, suggests that the present rotationally cool rate-coefficient measurement was performed at 380-130+50 K and that this is the lowest rotational temperature so far realized in storage-ring rate-coefficient measurements on H3+. This partially supports the theoretical suggestion that temperatures higher than assumed in earlier experiments are the main cause for the large gap between the experimental and the theoretical rate coefficients. For the rotationally hot rate-coefficient measurement a temperature of below 3250 K is derived. From these higher-temperature results it is found that increasing the rotational ion temperature in the calculations cannot fully close the gap between the theoretical and the experimental rate coefficients.

Storage Rings in the Sky: Gamma Ray Bursts and Galactic Gravitational Collapse Stored Energy

NASA Astrophysics Data System (ADS)

Greyber, H. D.

2004-05-01

The recent discovery of almost 100% polarization of the prompt gamma ray emission from GRB021206, (1), confirms my 44 year old ``Strong" Magnetic Field" model (SMF) for galactic dynamics. In SMF, Storage Ring particles were accelerated long ago during the original gravitational collapse of the pregalactic/prequasar plasma cloud that is permeated by an almost uniform primordial magnetic field (2,3) The enormous, intense, slender, relativistic, stable, completely coherent Storage Ring stores a very small fraction of the huge galactic gravitational collapse energy in an almost radiationless state, unless disturbed. The concept of an Astrophysical Storage Ring was introduced by me in l961. At first it was to explain galactic structure, but soon it proved useful to explain active galactic nuclei (AGN) and the dynamics of quasar/AGN jets. AGN and galactic morphology, energetics and dynamics vary as the ratio of magnetic energy to rotational energy in the particular object. Gamma ray bursts (GRB) are due simply to a ``rock". i.e. a white dwarf, ordinary star, neutron sstar, asteroid, planet, etc. falling rapidly through the Storage Ring and being almost instantly vaporized into a hot plasma fireball, causing an electromagnetic shower (2) Then the fireball speeds into the huge organized magnetic field surrounding the current ring, thus generating very highly polarized prompt gamma ray emission (as seen in GRB021206) from the synchrotron radiation process. The timing fits the GRB observations nicely. For instance, a ``rock" racing at 1000 kilometers per second across a 20,000 km. path in the beam would produce a twenty second burst. Other times, a target might track across a short chord for a short burst. Space missions have shown that often typical currents in space plasmas are made up of slender filaments. Thus the puzzling less than one millisecond spikes observed in some GRB are simply describing the structure of that particular ring current at that particular time. 1. W. Coburn and S.E. Boggs, Nature, 423, 415, (2003) 2. H. D. Greyber in a book, After the Dark Ages: When Galaxies Were Young, eds. S.S. Holt and E. P. Smith, AIP Conference Proceedings 470, 388-396. (1998) 3. H. D. Greyber in a Space Telescope Science Institute Report: Poster Papers from their 2001 Spring Symposium, ``The Dark Universe: Matter, Energy and Gravity," ed. Mario Livio, published March 2003, (34-39)

CCD developments for particle colliders

NASA Astrophysics Data System (ADS)

Stefanov, Konstantin D.

2006-09-01

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. First set of prototype devices have been designed, manufactured and successfully tested, with second-generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype is in production.

Beamline front end for in-vacuum short period undulator at the photon factory storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyauchi, Hiroshi, E-mail: hiroshi.miyauchi@kek.jp; Department of Accelerator Science, School of High Energy Accelerator Science, SOKENDAI; Tahara, Toshihiro, E-mail: ttahara@post.kek.jp

The straight-section upgrade project of the Photon Factory created four new short straight sections capable of housing in-vacuum short period undulators. The first to fourth short period undulators SGU#17, SGU#03, SGU#01 and SGU#15 were installed at the 2.5-GeV Photon Factory storage ring in 2005, 2006, 2009 and 2013, respectively. The beamline front end for SGU#15 is described in this paper.

A storage ring experiment to detect a proton electric dipole moment

DOE PAGES

Anastassopoulos, V.; Andrianov, S.; Baartman, R.; ...

2016-11-29

We describe a new experiment to detect a permanent electric dipole moment of the proton with a sensitivity of 10 $-$29e cm by using polarized “magic” momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000 TeV.

A storage ring experiment to detect a proton electric dipole moment.

PubMed

Anastassopoulos, V; Andrianov, S; Baartman, R; Baessler, S; Bai, M; Benante, J; Berz, M; Blaskiewicz, M; Bowcock, T; Brown, K; Casey, B; Conte, M; Crnkovic, J D; D'Imperio, N; Fanourakis, G; Fedotov, A; Fierlinger, P; Fischer, W; Gaisser, M O; Giomataris, Y; Grosse-Perdekamp, M; Guidoboni, G; Hacıömeroğlu, S; Hoffstaetter, G; Huang, H; Incagli, M; Ivanov, A; Kawall, D; Kim, Y I; King, B; Koop, I A; Lazarus, D M; Lebedev, V; Lee, M J; Lee, S; Lee, Y H; Lehrach, A; Lenisa, P; Levi Sandri, P; Luccio, A U; Lyapin, A; MacKay, W; Maier, R; Makino, K; Malitsky, N; Marciano, W J; Meng, W; Meot, F; Metodiev, E M; Miceli, L; Moricciani, D; Morse, W M; Nagaitsev, S; Nayak, S K; Orlov, Y F; Ozben, C S; Park, S T; Pesce, A; Petrakou, E; Pile, P; Podobedov, B; Polychronakos, V; Pretz, J; Ptitsyn, V; Ramberg, E; Raparia, D; Rathmann, F; Rescia, S; Roser, T; Kamal Sayed, H; Semertzidis, Y K; Senichev, Y; Sidorin, A; Silenko, A; Simos, N; Stahl, A; Stephenson, E J; Ströher, H; Syphers, M J; Talman, J; Talman, R M; Tishchenko, V; Touramanis, C; Tsoupas, N; Venanzoni, G; Vetter, K; Vlassis, S; Won, E; Zavattini, G; Zelenski, A; Zioutas, K

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10 -29 e ⋅ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the standard model at the scale of 3000 TeV.

A storage ring experiment to detect a proton electric dipole moment

NASA Astrophysics Data System (ADS)

Anastassopoulos, V.; Andrianov, S.; Baartman, R.; Baessler, S.; Bai, M.; Benante, J.; Berz, M.; Blaskiewicz, M.; Bowcock, T.; Brown, K.; Casey, B.; Conte, M.; Crnkovic, J. D.; D'Imperio, N.; Fanourakis, G.; Fedotov, A.; Fierlinger, P.; Fischer, W.; Gaisser, M. O.; Giomataris, Y.; Grosse-Perdekamp, M.; Guidoboni, G.; Hacıömeroǧlu, S.; Hoffstaetter, G.; Huang, H.; Incagli, M.; Ivanov, A.; Kawall, D.; Kim, Y. I.; King, B.; Koop, I. A.; Lazarus, D. M.; Lebedev, V.; Lee, M. J.; Lee, S.; Lee, Y. H.; Lehrach, A.; Lenisa, P.; Levi Sandri, P.; Luccio, A. U.; Lyapin, A.; MacKay, W.; Maier, R.; Makino, K.; Malitsky, N.; Marciano, W. J.; Meng, W.; Meot, F.; Metodiev, E. M.; Miceli, L.; Moricciani, D.; Morse, W. M.; Nagaitsev, S.; Nayak, S. K.; Orlov, Y. F.; Ozben, C. S.; Park, S. T.; Pesce, A.; Petrakou, E.; Pile, P.; Podobedov, B.; Polychronakos, V.; Pretz, J.; Ptitsyn, V.; Ramberg, E.; Raparia, D.; Rathmann, F.; Rescia, S.; Roser, T.; Kamal Sayed, H.; Semertzidis, Y. K.; Senichev, Y.; Sidorin, A.; Silenko, A.; Simos, N.; Stahl, A.; Stephenson, E. J.; Ströher, H.; Syphers, M. J.; Talman, J.; Talman, R. M.; Tishchenko, V.; Touramanis, C.; Tsoupas, N.; Venanzoni, G.; Vetter, K.; Vlassis, S.; Won, E.; Zavattini, G.; Zelenski, A.; Zioutas, K.

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity of 10-29 e ṡ cm by using polarized "magic" momentum 0.7 GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the standard model at the scale of 3000 TeV.

FLSR - The Frankfurt low energy storage ring

NASA Astrophysics Data System (ADS)

Stiebing, K. E.; Alexandrov, V.; Dörner, R.; Enz, S.; Kazarinov, N. Yu.; Kruppi, T.; Schempp, A.; Schmidt Böcking, H.; Völp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

2010-02-01

An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut für Kernphysik der Johann Wolfgang Goethe-Universität Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

The Status of the Taiwan Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, C. C.; Wang, J. P.; Chen, J. R.

2010-06-23

NSRRC has been operating a 1.5 GeV synchrotron light source, the Taiwan Light Source (TLS), for over 15 years and has established a large user community. For the future development of synchrotron radiation research in Taiwan, a feasibility study report to construct a 3.0 GeV low-emittance storage ring, the Taiwan Photon Source (TPS), was issued in July 2005. The government approval of the TPS project was obtained in December 2007 and the machine will be built at current site of NSRRC. The project has progressed steadily since and reached several major milestones now: the architect firm has finished the sitemore » plan and civil design, the accelerator design has been fixed, and purchase of long-lead items begins its course. The TPS storage ring has a circumference of 518.4 meters with a concentric booster of 496.8 meters. The storage ring adopted a 24-cell double-bend structure with a 1.6 nm-rad natural emittance. There are six 12-m and eighteen 7-m ID straights. For user research, five new beamlines have been selected for the Phase I operations: the micro protein crystallography, the materials sub-micron diffraction, the inelastic soft x-ray scattering, the coherent x-ray scattering, and the nano probe beamlines. The civil construction is getting ready to start. The commissioning of the TPS storage ring is targeted for 2013.« less

Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

NASA Astrophysics Data System (ADS)

Xu, Wei; Li, Jing-Yi; Huang, Sen-Lin; Z. Wu, W.; Hao, H.; P., Wang; K. Wu, Y.

2014-10-01

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

Zeroth-order design report for the next linear collider. Volume 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raubenheimer, T.O.

1996-05-01

This Zeroth Order Design Report (ZDR) for the Next Linear Collider (NLC) has been completed as a feasibility study for a TeV-scale linear collider that incorporates a room-temperature accelerator powered by rf microwaves at 11.424 GHz--similar to that presently used in the SLC, but at four times the rf frequency. The purpose of this study is to examine the complete systems of such a collider, to understand how the parts fit together, and to make certain that every required piece has been included. The design presented here is not fully engineered in any sense, but to be assured that themore » NLC can be built, attention has been given to a number of critical components and issues that present special challenges. More engineering and development of a number of mechanical and electrical systems remain to be done, but the conclusion of this study is that indeed the NLC is technically feasible and can be expected to reach the performance levels required to perform research at the TeV energy scale. Volume one covers the following: the introduction; electron source; positron source; NLC damping rings; bunch compressors and prelinac; low-frequency linacs and compressors; main linacs; design and dynamics; and RF systems for main linacs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daugherty, W.; Mcwilliams, A.; Skidmore, E.

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to provide a technical basismore » to extend that period. This paper describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior and leak performance. The CSR behavior of O-rings was evaluated at temperatures from 79 °C to 177 °C. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 75 °C). O-rings were also aged in Primary Containment Vessel (PCV) fixtures at temperatures ranging from 79 °C to 232 °C. The fixtures are helium leak tested periodically to determine if they remain leak-tight. The PCV fixture tests demonstrate that the 9975 O-rings will remain leak-tight at temperatures up to 149 °C for 3 years or more, and no leak failures have been observed with up to 8 years aging at 93 °C. Significantly longer periods of leak-tight service are expected at the lower temperatures actually experienced in the storage environment. The predictive model developed from the CSR data conservatively indicates a service life of more than 20 years at the bounding temperature of 75 °C. Although the relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance to date.« less

Dark matter phenomenology of high-speed galaxy cluster collisions

DOE PAGES

Mishchenko, Yuriy; Ji, Chueng-Ryong

2017-07-29

Here, we perform a general computational analysis of possible post-collision mass distributions in high-speed galaxy cluster collisions in the presence of self-interacting dark matter. Using this analysis, we show that astrophysically weakly self-interacting dark matter can impart subtle yet measurable features in the mass distributions of colliding galaxy clusters even without significant disruptions to the dark matter halos of the colliding galaxy clusters themselves. Most profound such evidence is found to reside in the tails of dark matter halos’ distributions, in the space between the colliding galaxy clusters. Such features appear in our simulations as shells of scattered dark mattermore » expanding in alignment with the outgoing original galaxy clusters, contributing significant densities to projected mass distributions at large distances from collision centers and large scattering angles of up to 90°. Our simulations indicate that as much as 20% of the total collision’s mass may be deposited into such structures without noticeable disruptions to the main galaxy clusters. Such structures at large scattering angles are forbidden in purely gravitational high-speed galaxy cluster collisions.Convincing identification of such structures in real colliding galaxy clusters would be a clear indication of the self-interacting nature of dark matter. Our findings may offer an explanation for the ring-like dark matter feature recently identified in the long-range reconstructions of the mass distribution of the colliding galaxy cluster CL0024+017.« less

Dark matter phenomenology of high-speed galaxy cluster collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishchenko, Yuriy; Ji, Chueng-Ryong

Here, we perform a general computational analysis of possible post-collision mass distributions in high-speed galaxy cluster collisions in the presence of self-interacting dark matter. Using this analysis, we show that astrophysically weakly self-interacting dark matter can impart subtle yet measurable features in the mass distributions of colliding galaxy clusters even without significant disruptions to the dark matter halos of the colliding galaxy clusters themselves. Most profound such evidence is found to reside in the tails of dark matter halos’ distributions, in the space between the colliding galaxy clusters. Such features appear in our simulations as shells of scattered dark mattermore » expanding in alignment with the outgoing original galaxy clusters, contributing significant densities to projected mass distributions at large distances from collision centers and large scattering angles of up to 90°. Our simulations indicate that as much as 20% of the total collision’s mass may be deposited into such structures without noticeable disruptions to the main galaxy clusters. Such structures at large scattering angles are forbidden in purely gravitational high-speed galaxy cluster collisions.Convincing identification of such structures in real colliding galaxy clusters would be a clear indication of the self-interacting nature of dark matter. Our findings may offer an explanation for the ring-like dark matter feature recently identified in the long-range reconstructions of the mass distribution of the colliding galaxy cluster CL0024+017.« less

Design of 3 GeV booster ring lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Etisken, O., E-mail: ozgur.etisken@cern.ch; Ciftci, A. K., E-mail: abbas.kenan.ciftci@cern.ch

2016-03-25

The aim of this study is to design of a 3 GeV booster ring for the 3 GeV storage ring. Electrons are needed to be accelerated to 3.0 GeV from 0.15 GeV energy. In this frame, we studied on two options for booster ring; a compact booster and the booster that shares the same tunnel with the storage ring. The lattice type has been chosen FODO for both options, lattice parameters are calculated, sextupole magnets are used to decrease dynamic aperture problem and dynamic aperture calculations are also made with considering of the necessary conditions. After designing and calculating ofmore » the parameters, these designs have been compared with each other. In addition to this comparison, these booster design parameters have been compared with some world centers design parameters and the reliability of the booster design is seen. Beam optics, OPA and Elegant simulation programs have been used in the study calculations.« less

Strings, vortex rings, and modes of instability

DOE PAGES

Gubser, Steven S.; Nayar, Revant; Parikh, Sarthak

2015-01-12

We treat string propagation and interaction in the presence of a background Neveu–Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scalemore » which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross–Pitaevskii Lagrangian, and also how it compares to the action for giant gravitons.« less

High-speed schlieren videography of vortex-ring impact on a wall

NASA Astrophysics Data System (ADS)

Kissner, Benjamin; Hargather, Michael; Settles, Gary

2011-11-01

Ring vortices of approximately 20 cm diameter are generated through the use of an Airzooka toy. To make the vortex visible, it is seeded with difluoroethane gas, producing a refractive-index difference with the air. A 1-meter-diameter, single-mirror, double-pass schlieren system is used to visualize the ring-vortex motion, and also to provide the wall with which the vortex collides. High-speed imaging is provided by a Photron SA-1 digital video camera. The Airzooka is fired toward the mirror almost along the optical axis of the schlieren system, so that the view of the vortex-mirror collision is normal to the path of vortex motion. Vortex-wall interactions similar to those first observed by Walker et al. (JFM 181, 1987) are recorded at high speed. The presentation will consist of a screening and discussion of these video results.

Beam dynamics issues in linear colliders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seeman, J.T.

1989-06-01

The primary goal of present and future linear colliders is to maximize the integrated luminosity for the experimental program. Beam dynamics plays a central role in the maximization of integrated luminosity. It is the major issue in the production of small beam sizes and low experimental backgrounds and is also an important factor in the production of particle numbers, in the acceleration process, and in the number of bunches. The beam dynamics effects on bunches which are extracted from the damping rings, accelerated in the linac, collimated, momentum analyzed, and finally delivered to the final focus are reviewed. The effectsmore » of bunch compression, transverse and longitudinal wakefields, BNS damping, energy definition, dispersion, emittance, bunch aspect ratio, feedback, and stability are all important. 11 refs., 1 tab.« less

[The CERN and the megascience].

PubMed

Aguilar Peris, José

2006-01-01

In this work we analyse the biggest particle accelerator in the world: the LHC (Large Hadron Collider). The ring shaped tunnel is 27 km long and it is buried over 110 meters underground, straddling the border betwen France and Switzerland at the CERN laboratory near Geneva. Its mission is to recreate the conditions that existed shortly after the Big-Bang and to look for the hypothesised Higgs particle. The LHC will accelerate protons near the speed of the light and collide them head on at an energy of to 14 TeV (1 TeV = 10(12) eV). Keeping such high energy in the proton beams requires enormous magnetic fields which are generated by superconducting electromagnets chilled to less than two degrees above absolute zero. It is expected that LHC will be inaugurated in summer 2007.

Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

NASA Astrophysics Data System (ADS)

Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

2014-08-01

The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

Intra-Beam Scattering, Impedance, and Instabilities in Ultimate Storage Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bane, Karl; /SLAC

We have investigated collective effects in an ultimate storage ring, i.e. one with diffraction limited emittances in both planes, using PEP-X as an example. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, a 4.5 GeV ring running round beams at 200 mA in 3300 bunches, IBS doubles the emittances to 11.5 pm at the design current. The Touschek lifetime is 11 hours. Impedance driven collective effects tend not to be important since the beam current is relatively low. We have investigated collective effects in PEP-X, an ultimate storage ring, i.e.more » one with diffraction limited emittances (at one angstrom wavelength) in both planes. In an ultimate ring intra-beam scattering (IBS) sets the limit of current that can be stored. In PEP-X, IBS doubles the emittances to 11.5 pm at the design current of 200 mA, assuming round beams. The Touschek lifetime is quite large in PEP-X, 11.6 hours, and - near the operating point - increases with decreasing emittance. It is, however, a very sensitive function of momentum acceptance. In an ultimate ring like PEP-X impedance driven collective effects tend not to be important since the beam current is relatively low. Before ultimate PEP-X can be realized, the question of how to run a machine with round beams needs serious study. For example, in this report we assumed that the vertical emittance is coupling dominated. It may turn out that using vertical dispersion is a preferable way to generate round beams. The choice will affect IBS and the Touschek effect.« less

Properties of the electron cloud in a high-energy positron and electron storage ring

DOE PAGES

Harkay, K. C.; Rosenberg, R. A.

2003-03-20

Low-energy, background electrons are ubiquitous in high-energy particle accelerators. Under certain conditions, interactions between this electron cloud and the high-energy beam can give rise to numerous effects that can seriously degrade the accelerator performance. These effects range from vacuum degradation to collective beam instabilities and emittance blowup. Although electron-cloud effects were first observed two decades ago in a few proton storage rings, they have in recent years been widely observed and intensely studied in positron and proton rings. Electron-cloud diagnostics developed at the Advanced Photon Source enabled for the first time detailed, direct characterization of the electron-cloud properties in amore » positron and electron storage ring. From in situ measurements of the electron flux and energy distribution at the vacuum chamber wall, electron-cloud production mechanisms and details of the beam-cloud interaction can be inferred. A significant longitudinal variation of the electron cloud is also observed, due primarily to geometrical details of the vacuum chamber. Furthermore, such experimental data can be used to provide realistic limits on key input parameters in modeling efforts, leading ultimately to greater confidence in predicting electron-cloud effects in future accelerators.« less

Status of NSLS-II Storage Ring Vacuum Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doom,L.; Hseuh,H.; Ferreira, M.

2009-05-04

National Synchrotron Light Source II (NSLS-II), being constructed at Brookhaven National Laboratory, is a 3-GeV, high-flux and high- brightness synchrotron radiation facility with a nominal current of 500 mA. The storage ring vacuum system will have extruded aluminium chambers with ante-chamber for photon fans and distributed NEG strip pumping. Discrete photon absorbers will be used to intercept the un-used bending magnet radiation. In-situ bakeout will be implemented to achieve fast conditioning during initial commissioning and after interventions.

Saw-tooth instability in storage rings: simulations and dynamical model

NASA Astrophysics Data System (ADS)

Migliorati, M.; Palumbo, L.; Dattoli, G.; Mezi, L.

1999-11-01

The saw-tooth instability in storage rings is studied by means of a time-domain simulation code which takes into account the self-induced wake fields. The results are compared with those from a dynamical heuristic model exploiting two coupled non-linear differential equations, accounting for the time behavior of the instability growth rate and for the anomalous growth of the energy spread. This model is shown to reproduce the characteristic features of the instability in a fairly satisfactory way.

A storage ring experiment to detect a proton electric dipole moment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastassopoulos, V.; Andrianov, S.; Baartman, R.

2016-11-01

A new experiment is described to detect a permanent electric dipole moment of the proton with a sensitivity ofmore » $$10^{-29}e\\cdot$$cm by using polarized "magic" momentum $0.7$~GeV/c protons in an all-electric storage ring. Systematic errors relevant to the experiment are discussed and techniques to address them are presented. The measurement is sensitive to new physics beyond the Standard Model at the scale of 3000~TeV.« less

Storage rings for spin-polarized hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, D.; Lovelace, R.V.E.; Lee, D.

1989-11-01

A strong-focusing storage ring is proposed for the long-term magnetic confinement of a collisional gas of neutral spin-polarized hydrogen atoms in the Za{l arrow} and Zb{l arrow} hyperfine states. The trap uses the interaction of the magnetic moments of the gas atoms with a static magnetic field. Laser cooling and evaporative cooling can be utilized to enhance the confinement and to offset the influence of viscous heating. An important application of the trap is to the attainment of Bose--Einstein condensation.

Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.

PubMed

Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

2017-10-06

Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.

Nitrile/Buna N Material Failure Assessment for an O-Ring used on the Gaseous Hydrogen Flow Control Valve (FCV) of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Wingard, Doug

2006-01-01

After the rollout of Space Shuttle Discovery in April 2005 in preparation for return-to-flight, there was a failure of the Orbiter (OV-103) helium signature leak test in the gaseous hydrogen (GH2) system. Leakage was attributed to the Flow Control Valve (FCV) in Main Engine 3. The FCV determined to be the source of the leak for OV-103 is designated as LV-58. The nitrile/Buna N rubber O-ring seal was removed from LV-58, and failure analysis indicated radial cracks providing leak paths in one quadrant. Cracks were eventually found in 6 of 9 FCV O-rings among the three Shuttle Orbiters, though none were as severe as those for LV-58, OV-103. Testing by EM10 at MSFC on all 9 FCV O- rings included: laser dimensional, Shore A hardness and properties from a dynamic mechanical analyzer (DMA) and an Instron tensile machine. The following test data was obtained on the cracked quadrant of the LV-58, OV-103 O-ring: (1) the estimated compression set was only 9.5%, compared to none for the rest of the O-ring; (2) Shore A hardness for the O.D. was higher by almost 4 durometer points than for the rest of the O-ring; and (3) DMA data showed that the storage/elastic modulus E was almost 25% lower than for the rest of the O-ring. Of the 8 FCV O-rings tested on an Instron, 4 yielded tensile strengths that were below the MIL spec requirement of 1350 psi-a likely influence of rubber cracking. Comparisons were made between values of modulus determined by DNA (elastic) and Instron (Young s). Each nitrile/Buna N O-ring used in the FCV conforms to the MIL-P-25732C specification. A number of such O-rings taken from shelf storage at MSFC and Kennedy Space Center (KSC) were used to generate a reference curve of DMA glass transition temperature (Tg) vs. shelf storage time ranging from 8 to 26 years. A similar reference curve of TGA onset temperature (of rubber weight loss) vs. shelf storage time was also generated. The DMA and TGA data for the used FCV O-rings were compared to the reference curves. Correlations were also made between the DMA modulus (at 22 C) and Shore A hardness for all 9 of the FCV O-rings used among the three Shuttle Orbiters. The radial cracking in the FCV O-rings was determined to be due to ozone attack, as nitrile/Buna N rubber is susceptible to such attack. Nitrile/Buna N material under MIL-P25732C should be used in a hydraulic fluid environment to help protect it from cracking. However, the FCV O-rings were used in an air only environment. The FCV design has as much as a 9-mil gap that allows the O.D. of the O-ring to be directly exposed to ozone, pressurized air and some elevated temperatures, accelerating the weathering process that leads to O-ring cracking. Space Shuttle flights will likely not continue past 2010. Therefore, Shuttle management decided to continue using the nitrile/Buna N material for the FCVs, but have each O-ring replaced after 3 years to minimize any chances for crack initiation.

Flexible matrix composite laminated disk/ring flywheel

NASA Technical Reports Server (NTRS)

Gupta, B. P.; Hannibal, A. J.

1984-01-01

An energy storage flywheel consisting of a quasi-isotropic composite disk overwrapped by a circumferentially wound ring made of carbon fiber and a elastometric matrix is proposed. Through analysis it was demonstrated that with an elastomeric matrix to relieve the radial stresses, a laminated disk/ring flywheel can be designed to store a least 80.3 Wh/kg or about 68% more than previous disk/ring designs. at the same time the simple construction is preserved.

Superconducting Magnet Technology for Future High Energy Proton Colliders

NASA Astrophysics Data System (ADS)

Gourlay, Stephen

2017-01-01

Interest in high field dipoles has been given a boost by new proposals to build a high-energy proton-proton collider to follow the LHC and programs around the world are taking on the task to answer the need. Studies aiming toward future high-energy proton-proton colliders at the 100 TeV scale are now being organized. The LHC and current cost models are based on technology close to four decades old and point to a broad optimum of operation using dipoles with fields between 5 and 12T when site constraints, either geographical or political, are not a factor. Site geography constraints that limit the ring circumference can drive the required dipole field up to 20T, which is more than a factor of two beyond state-of-the-art. After a brief review of current progress, the talk will describe the challenges facing future development and present a roadmap for moving high field accelerator magnet technology forward. This work was supported by the Director, Office of Science, High Energy Physics, US Department of Energy, under contract No. DE-AC02-05CH11231.

nuSTORM and A Path to a Muon Collider

DOE PAGES

Adey, David; Bayes, Ryan; Bross, Alan; ...

2015-05-20

Our article reviews the current status of the nuSTORM facility and shows how it can be utilized to perform the next step on the path toward the realization of a μ +μ - collider. This review includes the physics motivation behind nuSTORM, a detailed description of the facility and the neutrino beams it can produce, and a summary of the short-baseline neutrino oscillation physics program that can be carried out at the facility. The idea for nuSTORM (the production of neutrino beams from the decay of muons in a racetrack-like decay ring) was discussed in the literature more than 30more » years ago in the context of searching for noninteracting (sterile) neutrinos. However, only in the past 5 years has the concept been fully developed, motivated in large part by the facility's unmatched reach in addressing the evolving data on oscillations involving sterile neutrinos. Finally, this article reviews the basics of the μ +μ -collider concept and describes how nuSTORM provides a platform to test advanced concepts for six-dimensional muon ionization cooling.« less

Electric dipole moment planning with a resurrected BNL Alternating Gradient Synchrotron electron analog ring

NASA Astrophysics Data System (ADS)

Talman, Richard M.; Talman, John D.

2015-07-01

There has been much recent interest in directly measuring the electric dipole moments (EDM) of the proton and the electron, because of their possible importance in the present day observed matter/antimatter imbalance in the Universe. Such a measurement will require storing a polarized beam of "frozen spin" particles, 15 MeV electrons or 230 MeV protons, in an all-electric storage ring. Only one such relativistic electric accelerator has ever been built—the 10 MeV "electron analog" ring at Brookhaven National Laboratory in 1954; it can also be referred to as the "AGS analog" ring to make clear it was a prototype for the Alternating Gradient Synchrotron (AGS) proton ring under construction at that time at BNL. (Its purpose was to investigate nonlinear resonances as well as passage through "transition" with the newly invented alternating gradient proton ring design.) By chance this electron ring, long since dismantled and its engineering drawings disappeared, would have been appropriate both for measuring the electron EDM and to serve as an inexpensive prototype for the arguably more promising, but 10 times more expensive, proton EDM measurement. Today it is cheaper yet to "resurrect" the electron analog ring by simulating its performance computationally. This is one purpose for the present paper. Most existing accelerator simulation codes cannot be used for this purpose because they implicitly assume magnetic bending. The new ual/eteapot code, described in detail in an accompanying paper, has been developed for modeling storage ring performance, including spin evolution, in electric rings. Illustrating its use, comparing its predictions with the old observations, and describing new expectations concerning spin evolution and code performance, are other goals of the paper. To set up some of these calculations has required a kind of "archeological physics" to reconstitute the detailed electron analog lattice design from a 1991 retrospective report by Plotkin as well as unpublished notes of Courant describing machine studies performed in 1954-1955. This paper describes the practical application of the eteapot code and provides sample results, with emphasis on emulating lattice optics in the AGS analog ring for comparison with the historical machine studies and to predict the electron spin evolution they would have measured if they had polarized electrons and electron polarimetry. Of greater present day interest is the performance to be expected for a proton storage ring experiment. To exhibit the eteapot code performance and confirm its symplecticity, results are also given for 30 million turn proton spin tracking in an all-electric lattice that would be appropriate for a present day measurement of the proton EDM. The accompanying paper "Symplectic orbit and spin tracking code for all-electric storage rings" documents in detail the theoretical formulation implemented in eteapot, which is a new module in the Unified Accelerator Libraries (ual) environment.

Design of superconducting corrector magnets for LHC

NASA Astrophysics Data System (ADS)

Baynham, D. E.; Coombs, R. C.; Ijspeert, A.; Perin, R.

1994-07-01

The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to each main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented.

The Realm of Daphnis

NASA Image and Video Library

2017-02-14

Daphnis, one of Saturn's ring-embedded moons, is featured in this view, kicking up waves as it orbits within the Keeler gap. The mosaic combines several images to show more waves in the gap edges. Daphnis is a small moon at 5 miles (8 kilometers) across, but its gravity is powerful enough to disrupt the tiny particles of the A ring that form the Keeler gap's edge. As the moon moves through the Keeler gap, wave-like features are created in both the horizontal and vertical plane. Images like this provide scientists with a close-up view of the complicated interactions between a moon and the rings, as well as the interactions between the ring particles themselves, in the wake of the moon's passage. Three wave crests of diminishing sizes trail Daphnis here. In each subsequent crest, the shape of the wave evolves, as the ring particles within the crests collide with one another. Close examination of Daphnis' immediate vicinity also reveals a faint, thin strand of ring material that almost appears to have been directly ripped out of the A ring by Daphnis. The images in this mosaic were taken in visible light, using the Cassini spacecraft narrow-angle camera at a distance of approximately 17,000 miles (28,000 kilometers) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 71 degrees. Image scale is 551 feet (168 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA17212

Phase measurement for driven spin oscillations in a storage ring

NASA Astrophysics Data System (ADS)

Hempelmann, N.; Hejny, V.; Pretz, J.; Soltner, H.; Augustyniak, W.; Bagdasarian, Z.; Bai, M.; Barion, L.; Berz, M.; Chekmenev, S.; Ciullo, G.; Dymov, S.; Eversmann, D.; Gaisser, M.; Gebel, R.; Grigoryev, K.; Grzonka, D.; Guidoboni, G.; Heberling, D.; Hetzel, J.; Hinder, F.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Koop, I.; Kulikov, A.; Lehrach, A.; Lenisa, P.; Lomidze, N.; Lorentz, B.; Maanen, P.; Macharashvili, G.; Magiera, A.; Mchedlishvili, D.; Mey, S.; Müller, F.; Nass, A.; Nikolaev, N. N.; Nioradze, M.; Pesce, A.; Prasuhn, D.; Rathmann, F.; Rosenthal, M.; Saleev, A.; Schmidt, V.; Semertzidis, Y.; Senichev, Y.; Shmakova, V.; Silenko, A.; Slim, J.; Stahl, A.; Stassen, R.; Stephenson, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Tagliente, G.; Talman, R.; Thörngren Engblom, P.; Trinkel, F.; Uzikov, Yu.; Valdau, Yu.; Valetov, E.; Vassiliev, A.; Weidemann, C.; Wrońska, A.; Wüstner, P.; Zuprański, P.; Żurek, M.; JEDI Collaboration

2018-04-01

This paper reports the first simultaneous measurement of the horizontal and vertical components of the polarization vector in a storage ring under the influence of a radio frequency (rf) solenoid. The experiments were performed at the Cooler Synchrotron COSY in Jülich using a vector polarized, bunched 0.97 GeV /c deuteron beam. Using the new spin feedback system, we set the initial phase difference between the solenoid field and the precession of the polarization vector to a predefined value. The feedback system was then switched off, allowing the phase difference to change over time, and the solenoid was switched on to rotate the polarization vector. We observed an oscillation of the vertical polarization component and the phase difference. The oscillations can be described using an analytical model. The results of this experiment also apply to other rf devices with horizontal magnetic fields, such as Wien filters. The precise manipulation of particle spins in storage rings is a prerequisite for measuring the electric dipole moment (EDM) of charged particles.

EUTERPE, a small electron storage ring for XRF

NASA Astrophysics Data System (ADS)

Botman, J. I. M.; Mutsaers, P. H. A.; Hagedoorn, H. L.; De Voigt, M. J. A.

1990-04-01

A small-sized electron storage ring is under construction at the Eindhoven University of Technology which will cover the energy range of 15 to 400 MeV. At top energy the characteristic wavelength of the synchrotron radiation spectrum is 8.3 nm for the regular dipole magnets and 1.2 nm corresponding to 1.06 keV for a 10 T wiggler magnet. This will provide useful radiation for X-ray fluorescence (XRF) up to 3.2 keV. Alternatively, photon conversion with a high power CO 2 laser beam of 0.124 eV photons will generate X-rays for XRF with energies ranging from 0.5 to 300 keV, depending on the operating energy of the storage ring. This facility will provide an important extension to the activities of the Eindhoven group on PIXE, RBS and microbeam analysis. A short description of the macnine will be given together with applications and specific examples of the XRF method.

Magnetic Measurements of Storage Ring Magnets for the APS Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doose, C.; Dejus, R.; Jaski, M.

2017-06-01

Extensive prototyping of storage ring magnets is ongoing at the Advanced Photon Source (APS) in support of the APS Multi-Bend Achromat (MBA) upgrade project (APS-U) [1]. As part of the R&D activities four quadrupole magnets with slightly different geometries and pole tip materials, and one sextupole magnet with vanadium permendur (VP) pole tips were designed, built and tested. Magnets were measured individually using a rotating coil and a Hall probe for detailed mapping of the magnetic field. Magnets were then assembled and aligned relative to each other on a steel support plate and concrete plinth using precision machined surfaces tomore » gain experience with the alignment method chosen for the APS-U storage ring magnets. The required alignment of magnets on a common support structure is 30 μm rms. Measurements of magnetic field quality, strength and magnet alignment after subjecting the magnets and assemblies to different tests are presented.« less

Constrained multi-objective optimization of storage ring lattices

NASA Astrophysics Data System (ADS)

Husain, Riyasat; Ghodke, A. D.

2018-03-01

The storage ring lattice optimization is a class of constrained multi-objective optimization problem, where in addition to low beam emittance, a large dynamic aperture for good injection efficiency and improved beam lifetime are also desirable. The convergence and computation times are of great concern for the optimization algorithms, as various objectives are to be optimized and a number of accelerator parameters to be varied over a large span with several constraints. In this paper, a study of storage ring lattice optimization using differential evolution is presented. The optimization results are compared with two most widely used optimization techniques in accelerators-genetic algorithm and particle swarm optimization. It is found that the differential evolution produces a better Pareto optimal front in reasonable computation time between two conflicting objectives-beam emittance and dispersion function in the straight section. The differential evolution was used, extensively, for the optimization of linear and nonlinear lattices of Indus-2 for exploring various operational modes within the magnet power supply capabilities.

ACCELERATORS: Beam based alignment of the SSRF storage ring

NASA Astrophysics Data System (ADS)

Zhang, Man-Zhou; Li, Hao-Hu; Jiang, Bo-Cheng; Liu, Gui-Min; Li, De-Ming

2009-04-01

There are 140 beam position monitors (BPMs) in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment (BBA) method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.

Symplectic orbit and spin tracking code for all-electric storage rings

DOE PAGES

Talman, Richard M.; Talman, John D.

2015-07-22

Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring “trap.” At the “magic” kinetic energy of 232.792 MeV, proton spins are “frozen,” for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10 –29e–cm or greater will produce a statisticallymore » significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial “symplectification”). Any residual spurious damping or antidamping is sufficiently small to permit reliable tracking for the long times, such as the 1000 s assumed in estimating the achievable EDM precision. This paper documents in detail the theoretical formulation implemented in eteapot. An accompanying paper describes the practical application of the eteapot code in the Universal Accelerator Libraries (ual) environment to “resurrect,” or reverse engineer, the “AGS-analog” all-electric ring built at Brookhaven National Laboratory in 1954. Of the (very few) all-electric rings ever commissioned, the AGS-analog ring is the only relativistic one and is the closest to what is needed for measuring proton (or, even more so, electron) EDM’s. As a result, the companion paper also describes preliminary lattice studies for the planned proton EDM storage rings as well as testing the code for long time orbit and spin tracking.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eriksson, Mikael

Not very long ago, the 3{sup rd} generation storage ring technology was judged as mature. Most of the 3{sup rd} generation storage rings used the Double-Bend Achromat (DBA) or Triple-Bend Achromat (TBA) concepts. It was however a well-known fact that increasing the number of magnet cells in the rings is a powerful way of decreasing the electron beam emittance and thus the source brilliance, but at the penalty of increasing the size and cost of the rings. Preserving the Dynamic Aperture (DA) in the rings became also an issue when increasing the number of magnet cells. The Multi-Bend Achromat (MBA)more » concept, including a miniaturization of the ring elements, has now drastically changed the picture. The MBA rings, now in construction or being planned, offer orders of magnitudes higher brilliance than rings of conventional designs. Several light sources around the world are now implementing or planning to implement this MBA concept. This article touches on the science drivers for higher brilliance. We will then describe the MBA concept with its advantages as well as its challenges. A short survey of the MBA activity around the world will also be presented. The author apologies for focusing on the MAX IV project regarding technical solutions. This is motivated by that MAX IV is the facility he knows best and it might be regarded as a fore-runner for the MBA concept.« less

The Abort Kicker System for the PEP-II Storage Rings at SLAC.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delamare, Jeffrey E

2003-06-20

The PEP-II project has two storage rings. The HER (High Energy Ring) has up to 1.48 A of election beam at 9 GeV, and the LER (Low Energy Ring) has up to 2.14 A of positron beam at 3.1 GeV. To protect the HER and LER beam lines in the event of a ring component failure, each ring has an abort kicker system which directs the beam into a dump when a failure is detected. Due to the high current of the beams, the beam kick is tapered from 100% to 80% in 7.33 {micro}S (the beam transit time aroundmore » the ring). This taper distributes the energy evenly across the window which separates the ring from the beam dump such that the window is not damaged. The abort kicker trigger is synchronized with the ion clearing gap of the beam allowing for the kicker field to rise from 0-80% while there is no beam in the kicker magnet. Originally the kicker system was designed for a rise time of 370nS [1], but because the ion clearing gap was reduced in half, so was the rise time requirement for the kicker. This report discusses the design of the system interlocks, diagnostics, and modulator with the modifications necessary to accommodate an ion clearing gap of 185nS.« less

SUPERFAST THERMALIZATION OF PLASMA

DOEpatents

Chang, C.C.

1962-06-12

A method is given for the superfast thermalization of plasma by shock conversion of the kinetic energy stored in rotating plasma rings or plasmoids colliding at near supersonic speeds in a containment field to heat energy in the resultant confined plasma mass. The method includes means for generating rotating plasmoids at the opposite ends of a Pyrotron or Astron containment field. The plasmoids are magnetically accelerated towards each other into the opposite ends of time containment field. During acceleration of the plasmoids toward the center of the containment field, the intensity of the field is sequentially increased to adiabatically compress the plasmoids and increase the plasma energy. The plasmoids hence collide with a violent shock at the eenter of the containment field, causing the substantial kinetic energy stored in the plasmoids to be converted to heat in the resultant plasma mass. (AEC)

Resonant neutral-particle emission in collisions of electrons with peptide ions in a storage ring.

PubMed

Tanabe, T; Noda, K; Saito, M; Lee, S; Ito, Y; Takagi, H

2003-05-16

Electron-biomolecular ion collisions were studied using an electrostatic storage ring with a merging beam technique for singly protonated peptides (angiotensin I, II, and III). A strong neutral-particle emission at around 6.5 eV was found in addition to neutrals from recombination at low energies. The rates of the high-energy peak greatly decreased with a slight decrease in the number of amino-acid residues from angiotensin I to III. These results suggest that some peptide bonds were selectively cleaved.

Commissioning and Early Operation Experience of the NSLS-II Storage Ring RF System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, F.; Rose, J.; Cupolo, J.

2015-05-03

The National Synchrotron Light Source II (NSLS-II) is a 3 GeV electron X-ray user facility commissioned in 2014. The storage ring RF system, essential for replenishing energy loss per turn of the electrons, consists of digital low level RF controllers, 310 kW CW klystron transmitters, CESR-B type superconducting cavities, as well as a supporting cryogenic system. Here we will report on RF commissioning and early operation experience of the system for beam current up to 200mA.

Mass Measurements of Proton-rich Nuclides at the Cooler Storage Ring at IMP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Y. H.; Xu, H. S.; Wang, M.

2011-11-30

Recent results and progress of mass measurements of proton-rich nuclei using isochronous mass spectrometry (IMS) are reported. The nuclei under investigation were produced via fragmentation of relativistic energy heavy ions of {sup 78}Kr and {sup 58}Ni. After in-flight separation by the fragment separator RIBLL-2, the nuclei were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of the revolution times. The impact of these measurements on the stellar nucleosynthesis in the rp-process is discussed.

Conditioning of the vacuum system of the TPS storage ring without baking in situ

NASA Astrophysics Data System (ADS)

Chan, C. K.; Chang, C. C.; Shueh, C.; Yang, I. C.; Wu, L. H.; Chen, B. Y.; Cheng, C. M.; Huang, Y. T.; Chuang, J. Y.; Cheng, Y. T.; Hsiao, Y. M.; Sheng, Albert

2017-04-01

To shorten the machine downtime, a maintenance procedure without baking in situ has been developed and applied to maintain and to upgrade the vacuum system of the TPS storage ring. The data of photon-stimulated desorption (PSD) reveal no obvious discrepancy between baking and not baking the vacuum system in situ. A beam-conditioning dose of extent only 11.8 A h is required to recover quickly the dynamic pressure of an unbaked vacuum system to its pre-intervention value according to the TPS maintenance experience.

Natural variation in expression of genes associated with carotenoid biosynthesis and accumulation in cassava (Manihot esculenta Crantz) storage root.

PubMed

Carvalho, Luiz Jcb; Agustini, Marco Av; Anderson, James V; Vieira, Eduardo A; de Souza, Claudia Rb; Chen, Songbi; Schaal, Barbara A; Silva, Joseane P

2016-06-10

Cassava (Manihot esculenta Crantz) storage root provides a staple food source for millions of people worldwide. Increasing the carotenoid content in storage root of cassava could provide improved nutritional and health benefits. Because carotenoid accumulation has been associated with storage root color, this study characterized carotenoid profiles, and abundance of key transcripts associated with carotenoid biosynthesis, from 23 landraces of cassava storage root ranging in color from white-to-yellow-to-pink. This study provides important information to plant breeding programs aimed at improving cassava storage root nutritional quality. Among the 23 landraces, five carotenoid types were detected in storage root with white color, while carotenoid types ranged from 1 to 21 in storage root with pink and yellow color. The majority of storage root in these landraces ranged in color from pale-to-intense yellow. In this color group, total β-carotene, containing all-E-, 9-Z-, and 13-Z-β-carotene isomers, was the major carotenoid type detected, varying from 26.13 to 76.72 %. Although no α-carotene was observed, variable amounts of a α-ring derived xanthophyll, lutein, was detected; with greater accumulation of α-ring xanthophylls than of β-ring xanthophyll. Lycopene was detected in a landrace (Cas51) with pink color storage root, but it was not detected in storage root with yellow color. Based on microarray and qRT-PCR analyses, abundance of transcripts coding for enzymes involved in carotenoid biosynthesis were consistent with carotenoid composition determined by contrasting HPLC-Diode Array profiles from storage root of landraces IAC12, Cas64, and Cas51. Abundance of transcripts encoding for proteins regulating plastid division were also consistent with the observed differences in total β-carotene accumulation. Among the 23 cassava landraces with varying storage root color and diverse carotenoid types and profiles, landrace Cas51 (pink color storage root) had low LYCb transcript abundance, whereas landrace Cas64 (intense yellow storage root) had decreased HYb transcript abundance. These results may explain the increased amounts of lycopene and total β-carotene observed in landraces Cas51 and Cas64, respectively. Overall, total carotenoid content in cassava storage root of color class representatives were associated with spatial patterns of secondary growth, color, and abundance of transcripts linked to plastid division. Finally, a partial carotenoid biosynthesis pathway is proposed.

Gridded thermionic gun and integral superconducting ballistic bunch compression cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultheiss, Thomas

Electron-Ion colliders such as the Medium energy Electron Ion Collider (MEIC) being developed by JLAB require high current electrons with low energy spread for electron cooling of the collider ring. Accelerator techniques for improving bunch charge, average current, emittance, and energy spread are required for Energy Recovery Linacs (ERLs) and Circulator Rings (CR) for next generation colliders for nuclear physics experiments. Example candidates include thermionic-cathode electron guns with RF accelerating structures. Thermionic cathodes are known to produce high currents and have excellent lifetime. The success of the IR and THz Free-Electron Laser (FEL) designed and installed by Advanced Energy Systemsmore » at the Fritz Haber Institute (FHI) of the Max Planck Society in Berlin [1,2] demonstrates that gridded thermionic cathodes and rf systems be considered for next generation collider technology. In Phase 1 Advanced Energy Systems (AES) developed and analyzed a design concept using a superconducting cavity pair and gridded thermionic cathode. Analysis included Beam Dynamics and thermal analysis to show that a design of this type is feasible. The latest design goals for the MEIC electron cooler were for electron bunches of 420 pC at a frequency of 952.6 MHz with a magnetic field on the cathode of 2kG. This field magnetizes the beam imparting angular momentum that provides for helical motion of the electrons in the cooling solenoid. The helical motion increases the interaction time and improves the cooling efficiency. A coil positioned around the cathode providing 2kG field was developed. Beam dynamics simulations were run to develop the particle dynamics near the cathode and grid. Lloyd Young added capability to Tstep to include space charge effects between two plates and include image charge effects from the grid. He also added new pepper-pot geometry capability to account for honeycomb grids. These additions were used to develop the beam dynamics for this gun. The general design is a modified ballistic compression cavity pair with two independently powered cells [3]. The first is a cathode cell that includes the thermionic cathode and grid to provide for beam bunching. The second is a full cell with independent phasing and field levels designed to minimize energy spread. The primary goal for Phase II is to manufacture a superconducting gun with a thermionic cathode and imbedded coil. The system developed here is applicable to many high current electron accelerators. The analysis and design constraints imposed by the magnetized cathode make the cathode system developed here more complicated and limited than one without the magnetized beam constraints. High power ERLs would benefit by a gun with the capabilities shown here, 400 mA or more of current. ERLs hold great promise for electron cooling experiments, advanced light sources and Free Electron Lasers. This high current electron injector is a technological advance that will place the requirements for an ERL capable of providing quality bunches needed for cooling within the MEIC circulator ring within reach. This injector would have application to future ERLs around the world.« less

A 1kW EUV source for lithography based on FEL emission in a compact storage ring

NASA Astrophysics Data System (ADS)

Feser, Michael; Ruth, Ron; Loewen, Rod

2017-10-01

EUV has long been hailed as the next generation lithography technology. Its adoption into high volume manufacturing (HVM), however, has been delayed several technology nodes due to technical issues, many of which can be attributed to the EUV source performance. Today's EUV lithography scanners are powered by laser produce plasma (LPP) sources. They have issues with power scaling beyond 300 W, reliability and contamination. Free Electron Lasers (FELs) have been considered as an alternative EUV source. Advantages of accelerator based sources are the maturity of the accelerator technology, lack of debris/contamination, and ability to provide high power. Industry turned away from this technology because of the requirement to feed up to 10 scanners from one linear FEL to make it economically feasible, the large footprint, and generation of radioactive byproducts. All of these issues are overcome in the presented concept using a compact storage ring with steady-state FEL lasing action. At 1 kW output power, comparable cost and footprint to an LPP source, this source is ideally suited for use on a single scanner and promises reliable, contamination free operation. FEL action in the storage ring is sustained by operating the FEL well below the saturation regime and preserving the equilibrium low emittance and energy distribution of the ring.

About separation and collision of Saturn rings particles

NASA Astrophysics Data System (ADS)

Tchernyi, Vladimir

There is no yet clear picture of the origin of Saturn's rings. We follow importance of electromag-netic idea that rings could originate and form from the frozen particles of the protoplanetary cloud after the appearance of the magnetic field of Saturn due to electromagnetic interaction of icy particles with the planetary magnetic field. The Sun heats the rings weakly, temperature in the area of the rings is about 70-110 K. It makes possible the existence of the superconduct-ing substance in the space behind the belt of asteroids. Theoretical electromagnetic modeling demonstrates that superconductivity can be the physical reason of the origin of the sombrero of rings of Saturn from the frozen particles of the protoplanetary cloud. The sombrero appears during some time after magnetic field of planet appears. Finally, all the Kepler's orbits of the superconducting particles are localizing as a sombrero disk of rings in the magnetic equator plane, where the energy of particles in the magnetic field of Saturn has a minimum value. Recently space probe "Cassini" discovered collisions and separation of the Saturn's rings parti-cles. It is also important fact that from electromagnetic modeling follows possibility of collide of the rings particles on the vertical direction within the width of the sombrero. It could be a reason for the formation of the particles of the bigger size due to coalescence, until gravity and centrifugal force will destroy them to the particles of smaller size again. From the solution of the electromagnetic problem we will demonstrate how rings of Saturn could be originated from the iced particles located within the protoplanetary cloud. Before appearance of the magnetic field of Saturn all particles within the protoplanetary cloud are located on such an orbit as Kepler's, where there is a balance of the force of gravity and the centrifugal force. With the occurrence of the magnetic field of the Saturn the superconducting particles of the protoplane-tary cloud begin to demonstrate an ideal diamagnetism. Due to appearance of the third force of diamagnetic push-out particles start to interact with the magnetic field and all the orbits of the particles become to be involved in additional azimuth-orbital movement. As a result, eventually, during some time, all orbits of the particles of the protoplanetary cloud should come together to magnetic equator plane and create highly flattening disc around planet. For separa-tion and collision of the particles within the sombrero of rings from solution of electromagnetic problem follows that for two particles which are located on the same plane, both particles will be pushing each other and they will be holding separation distance in between them. Then for another situation both particles are located on the same axis but on the different planes, both particles will be attracting each other, they could even collide or stick together and form bigger pieces or lumps of ice. Both facts have an experimental conformation by Cassini mission. Reference: Tchernyi V.V. Origin of the Saturn rings: electromagnetic model of the sombrero rings formation. Chapter in book: Space Exploration Research. Editors: John H. Denis and Paul D. Aldridge. Series: Space Science, Exploration and Policies. ISBN: 978-1-60692-264-4. Hauppauge, NY, USA, Nova Science Publishers, 2009:

Beam measurements using visible synchrotron light at NSLS2 storage ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Weixing, E-mail: chengwx@bnl.gov; Bacha, Bel; Singh, Om

2016-07-27

Visible Synchrotron Light Monitor (SLM) diagnostic beamline has been designed and constructed at NSLS2 storage ring, to characterize the electron beam profile at various machine conditions. Due to the excellent alignment, SLM beamline was able to see the first visible light when beam was circulating the ring for the first turn. The beamline has been commissioned for the past year. Besides a normal CCD camera to monitor the beam profile, streak camera and gated camera are used to measure the longitudinal and transverse profile to understand the beam dynamics. Measurement results from these cameras will be presented in this paper.more » A time correlated single photon counting system (TCSPC) has also been setup to measure the single bunch purity.« less

Study of spatial resolution of coordinate detectors based on Gas Electron Multipliers

NASA Astrophysics Data System (ADS)

Kudryavtsev, V. N.; Maltsev, T. V.; Shekhtman, L. I.

2017-02-01

Spatial resolution of GEM-based tracking detectors is determined in the simulation and measured in the experiments. The simulation includes GEANT4 implemented transport of high energy electrons with careful accounting of atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing with accounting of diffusion, gas amplification fluctuations, distribution of signals on readout electrodes, electronics noise and particular algorithm of final coordinate calculation (center of gravity). The simulation demonstrates that the minimum of spatial resolution of about 10 μm can be achieved with a gas mixture of Ar -CO2 (75-25 %) at a strips pitch from 250 μm to 300 μm. At a larger pitch the resolution quickly degrades reaching 80-100 μm at a pitch of 460-500 μm. Spatial resolution of low-material triple-GEM detectors for the DEUTERON facility at the VEPP-3 storage ring is measured at the extracted beam facility of the VEPP-4 M collider. One-coordinate resolution of the DEUTERON detector is measured with electron beam of 500 MeV, 1 GeV and 3.5 GeV energies. The determined value of spatial resolution varies in the range from approximately 35 μm to 50 μm for orthogonal tracks in the experiments.

Optimal Model-Based Fault Estimation and Correction for Particle Accelerators and Industrial Plants Using Combined Support Vector Machines and First Principles Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sayyar-Rodsari, Bijan; Schweiger, Carl; /SLAC /Pavilion Technologies, Inc., Austin, TX

2010-08-25

Timely estimation of deviations from optimal performance in complex systems and the ability to identify corrective measures in response to the estimated parameter deviations has been the subject of extensive research over the past four decades. The implications in terms of lost revenue from costly industrial processes, operation of large-scale public works projects and the volume of the published literature on this topic clearly indicates the significance of the problem. Applications range from manufacturing industries (integrated circuits, automotive, etc.), to large-scale chemical plants, pharmaceutical production, power distribution grids, and avionics. In this project we investigated a new framework for buildingmore » parsimonious models that are suited for diagnosis and fault estimation of complex technical systems. We used Support Vector Machines (SVMs) to model potentially time-varying parameters of a First-Principles (FP) description of the process. The combined SVM & FP model was built (i.e. model parameters were trained) using constrained optimization techniques. We used the trained models to estimate faults affecting simulated beam lifetime. In the case where a large number of process inputs are required for model-based fault estimation, the proposed framework performs an optimal nonlinear principal component analysis of the large-scale input space, and creates a lower dimension feature space in which fault estimation results can be effectively presented to the operation personnel. To fulfill the main technical objectives of the Phase I research, our Phase I efforts have focused on: (1) SVM Training in a Combined Model Structure - We developed the software for the constrained training of the SVMs in a combined model structure, and successfully modeled the parameters of a first-principles model for beam lifetime with support vectors. (2) Higher-order Fidelity of the Combined Model - We used constrained training to ensure that the output of the SVM (i.e. the parameters of the beam lifetime model) are physically meaningful. (3) Numerical Efficiency of the Training - We investigated the numerical efficiency of the SVM training. More specifically, for the primal formulation of the training, we have developed a problem formulation that avoids the linear increase in the number of the constraints as a function of the number of data points. (4) Flexibility of Software Architecture - The software framework for the training of the support vector machines was designed to enable experimentation with different solvers. We experimented with two commonly used nonlinear solvers for our simulations. The primary application of interest for this project has been the sustained optimal operation of particle accelerators at the Stanford Linear Accelerator Center (SLAC). Particle storage rings are used for a variety of applications ranging from 'colliding beam' systems for high-energy physics research to highly collimated x-ray generators for synchrotron radiation science. Linear accelerators are also used for collider research such as International Linear Collider (ILC), as well as for free electron lasers, such as the Linear Coherent Light Source (LCLS) at SLAC. One common theme in the operation of storage rings and linear accelerators is the need to precisely control the particle beams over long periods of time with minimum beam loss and stable, yet challenging, beam parameters. We strongly believe that beyond applications in particle accelerators, the high fidelity and cost benefits of a combined model-based fault estimation/correction system will attract customers from a wide variety of commercial and scientific industries. Even though the acquisition of Pavilion Technologies, Inc. by Rockwell Automation Inc. in 2007 has altered the small business status of the Pavilion and it no longer qualifies for a Phase II funding, our findings in the course of the Phase I research have convinced us that further research will render a workable model-based fault estimation and correction for particle accelerators and industrial plants feasible.« less

View from Above

NASA Image and Video Library

2016-10-31

Saturn appears as a serene globe amid tranquil rings in this view from NASA's Cassini spacecraft. In reality, the planet's atmosphere is an ever-changing scene of high-speed winds and evolving weather patterns, punctuated by occasional large storms (see PIA14901). The rings, consist of countless icy particles, which are continually colliding. Such collisions play a key role in the rings' numerous waves and wakes, which are the manifestation of the subtle influence of Saturn's moons and, indeed, the planet itself. The long duration of the Cassini mission has allowed scientists to study how the atmosphere and rings of Saturn change over time, providing much-needed insights into this active planetary system. The view looks toward the sunlit side of the rings from about 41 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on July 16, 2016 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers. The view was acquired at a distance of approximately 1 million miles (2 million kilometers) from Saturn. Image scale is 68 miles (110 kilometers) per pixel. The view was obtained at a distance of approximately 752,000 miles (1.21 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 6 degrees. Image scale is 45 miles (72 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20502

Advanced Photon Source accelerator ultrahigh vacuum guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Noonan, J.

1994-03-01

In this document the authors summarize the following: (1) an overview of basic concepts of ultrahigh vacuum needed for the APS project, (2) a description of vacuum design and calculations for major parts of APS, including linac, linac waveguide, low energy undulator test line, positron accumulator ring (PAR), booster synchrotron ring, storage ring, and insertion devices, and (3) cleaning procedures of ultrahigh vacuum (UHV) components presently used at APS.

Emittance and lifetime measurement with damping wigglers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, G. M.; Shaftan, T., E-mail: shaftan@bnl.gov; Cheng, W. X.

National Synchrotron Light Source II (NSLS-II) is a new third-generation storage ring light source at Brookhaven National Laboratory. The storage ring design calls for small horizontal emittance (<1 nm-rad) and diffraction-limited vertical emittance at 12 keV (8 pm-rad). Achieving low value of the beam size will enable novel user experiments with nm-range spatial and meV-energy resolution. The high-brightness NSLS-II lattice has been realized by implementing 30-cell double bend achromatic cells producing the horizontal emittance of 2 nm rad and then halving it further by using several Damping Wigglers (DWs). This paper is focused on characterization of the DW effects inmore » the storage ring performance, namely, on reduction of the beam emittance, and corresponding changes in the energy spread and beam lifetime. The relevant beam parameters have been measured by the X-ray pinhole camera, beam position monitors, beam filling pattern monitor, and current transformers. In this paper, we compare the measured results of the beam performance with analytic estimates for the complement of the 3 DWs installed at the NSLS-II.« less

Higher-Order Systematic Effects in the Muon Beam-Spin Dynamics for Muon g-2

NASA Astrophysics Data System (ADS)

Crnkovic, Jason; Brown, Hugh; Krouppa, Brandon; Metodiev, Eric; Morse, William; Semertzidis, Yannis; Tishchenko, Vladimir

2016-03-01

The BNL Muon g-2 Experiment (E821) produced a precision measurement of the muon anomalous magnetic moment, where as the Fermilab Muon g-2 Experiment (E989) is an upgraded version of E821 that has a goal of producing a measurement with approximately 4 times more precision. Improving the precision requires a more detailed understanding of the experimental systematic effects, and so three higher-order systematic effects in the muon beam-spin dynamics have recently been found and estimated for E821. The beamline systematic effect originates from muon production in beamline spectrometers, as well as from muons traversing beamline bending magnets. The kicker systematic effect comes from a combination of the variation in time spent inside the muon storage ring across a muon bunch and the temporal structure of the storage ring kicker waveform. Finally, the detector systematic effect arises from a combination of the energy dependent muon equilibrium orbit in the storage ring, muon decay electron drift time, and decay electron detector acceptance effects. Brookhaven Natl Lab.

Development of an Abort Gap Monitor for High-Energy Proton Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beche, J.-F.; Byrd, J.; De Santis, S.

2004-11-10

The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the 'abort gap', and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider.« less

Development of an abort gap monitor for high-energy proton rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beche, Jean-Francois; Byrd, John; De Santis, Stefano

2004-05-03

The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitormore » based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider« less

JLEIC SRF cavity RF Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shaoheng; Guo, Jiquan; Wang, Haipeng

2016-05-01

The initial design of a low higher order modes (HOM) impedance superconducting RF (SRF) cavity is presented in this paper. The design of this SRF cavity is for the proposed Jefferson Lab Electron Ion Collider (JLEIC). The electron ring of JLEIC will operate with electrons of 3 to 10 GeV energy. The ion ring of JLEIC will operate with protons of up to 100 GeV energy. The bunch lengths in both rings are ~12 mm (RMS). In order to maintain the short bunch length in the ion ring, SRF cavities are adopted to provide large enough gradient. In the firstmore » phase of JLEIC, the PEP II RF cavities will be reused in the electron ring to lower the initial cost. The frequency of the SRF cavities is chosen to be the second harmonic of PEP II cavities, 952.6 MHz. In the second phase of JLEIC, the same frequency SRF cavities may replace the normal conducting PEP II cavities to achieve higher luminosity at high energy. At low energies, the synchro-tron radiation damping effect is quite weak, to avoid the coupled bunch instability caused by the intense closely-spaced electron bunches, low HOM impedance of the SRF cavities combined with longitudinal feedback sys-tem will be necessary.« less

Matching into the Helical Bunch Coalescing Channel for a High Luminosity Muon Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sy, Amy; Ankenbrandt, Charles; Derbenev, Yaroslav

2015-09-01

For high luminosity in a muon collider, muon bunches that have been cooled in the six-dimensional helical cooling channel (HCC) must be merged into a single bunch and further cooled in preparation for acceleration and transport to the collider ring. The helical bunch coalescing channel has been previously simulated and provides the most natural match from helical upstream and downstream subsystems. This work focuses on the matching from the exit of the multiple bunch HCC into the start of the helical bunch coalescing channel. The simulated helical matching section simultaneously matches the helical spatial period lambda in addition to providingmore » the necessary acceleration for efficient bunch coalescing. Previous studies assumed that the acceleration of muon bunches from p=209.15 MeV/c to 286.816 MeV/c and matching of lambda from 0.5 m to 1.0 m could be accomplished with zero particle losses and zero emittance growth in the individual bunches. This study demonstrates nonzero values for both particle loss and emittance growth, and provides considerations for reducing these adverse effects to best preserve high luminosity.« less

The magnetic toroidal sector: a broad-band electron-positron pair spectrometer

NASA Astrophysics Data System (ADS)

Hagmann, Siegbert; Hillenbrand, Pierre-Michel; Litvinov, Yuri; Spillmann, Uwe

2016-05-01

At the future relativistic storage-ring HESR at FAIR the study of electron-positron pairs from non-nuclear, atomic processes will be one of the goals of the experimental program with kinematically complete experiments focusing on momentum spectroscopy of coincident emission of electrons and positrons from free-free pairs and corresponding recoil ions. The underlying production mechanisms belong to central topics of QED in strong fields. We present first results on the electron-optical properties of a magnetic toroidal sector configuration enabling coincident detection of free-free electron-positron pairs; this spectrometer is suitable for implementation into a storage ring with a supersonic jet target and covering a wide range of lepton emission into the forward hemisphere. The simulation calculations are performed using the OPERA code.

MEIC electron cooling program

DOE PAGES

Derbenev, Yaroslav S.; Zhang, Yuhong

2014-12-01

Cooling of proton and ion beams is essential for achieving high luminosities (up to above 10 34 cm -2s -1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); themore » other is a high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.« less

Orthos, an alarm system for the ALICE DAQ operations

NASA Astrophysics Data System (ADS)

Chapeland, Sylvain; Carena, Franco; Carena, Wisla; Chibante Barroso, Vasco; Costa, Filippo; Denes, Ervin; Divia, Roberto; Fuchs, Ulrich; Grigore, Alexandru; Simonetti, Giuseppe; Soos, Csaba; Telesca, Adriana; Vande Vyvre, Pierre; von Haller, Barthelemy

2012-12-01

ALICE (A Large Ion Collider Experiment) is the heavy-ion detector studying the physics of strongly interacting matter and the quark-gluon plasma at the CERN LHC (Large Hadron Collider). The DAQ (Data Acquisition System) facilities handle the data flow from the detectors electronics up to the mass storage. The DAQ system is based on a large farm of commodity hardware consisting of more than 600 devices (Linux PCs, storage, network switches), and controls hundreds of distributed hardware and software components interacting together. This paper presents Orthos, the alarm system used to detect, log, report, and follow-up abnormal situations on the DAQ machines at the experimental area. The main objective of this package is to integrate alarm detection and notification mechanisms with a full-featured issues tracker, in order to prioritize, assign, and fix system failures optimally. This tool relies on a database repository with a logic engine, SQL interfaces to inject or query metrics, and dynamic web pages for user interaction. We describe the system architecture, the technologies used for the implementation, and the integration with existing monitoring tools.

3 GeV Booster Synchrotron Conceptual Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiedemann, Helmut

2009-06-02

Synchrotron light cna be produced from a relativistic particle beam circulating in a storage ring at extremely high intensity and brilliance over a large spectral region reaching from the far infrared regime to hard x-rays. The particles, either electrons or positrons, radiate as they are deflected in the fields of the storage ring bending magnets or of magnets specially optimized for the production of synchrotron light. The synchrotron light being very intense and well collimated in the forward direction has become a major tool in a large variety of research fields in physics, chemistry, material science, biology, and medicine.

Safe operating conditions for NSLS-II Storage Ring Frontends commissioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seletskiy, S.; Amundsen, C.; Ha, K.

2015-04-02

The NSLS-II Storage Ring Frontends are designed to safely accept the synchrotron radiation fan produced by respective insertion device when the electron beam orbit through the ID is locked inside the predefined Active Interlock Envelope. The Active Interlock is getting enabled at a particular beam current known as AI safe current limit. Below such current the beam orbit can be anywhere within the limits of the SR beam acceptance. During the FE commissioning the beam orbit is getting intentionally disturbed in the particular ID. In this paper we explore safe operating conditions for the Frontends commissioning.

DESY II, a new injector for the DESY storage rings PETRA and DORIS II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemmie, G.

1983-08-01

There is a proposal to build a new 9 GeV electron synchrotron as a dedicated injector for the storage rings DORIS and PETRA. This machine will be housed in the old DESY-tunnel side-by-side with the original DESY-synchrotron. It is characterized by a separated function lattice, a 12.5 Hz repetition frequency, an all-metal vacuum chamber and a high shunt impedance rf-system. After commissioning of this new machine in 1984, the old DESY-synchrotron could be converted into a dedicated proton-accelerator as part of the injection chain for HERA.

Explicit symplectic orbit and spin tracking method for electric storage ring

DOE PAGES

Hwang, Kilean; Lee, S. Y.

2016-08-18

We develop a symplectic charged particle tracking method for phase space coordinates and polarization in all electric storage rings. Near the magic energy, the spin precession tune is proportional to the fractional momentum deviation δ m from the magic energy, and the amplitude of the radial and longitudinal spin precession is proportional to η/δ m, where η is the electric dipole moment for an initially vertically polarized beam. As a result, the method can be used to extract the electron electric dipole moment of a charged particle by employing narrow band frequency analysis of polarization around the magic energy.

Experience with Round Beam Operation at The Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, A.; Emery, L.; Sajaev, V.

2015-01-01

Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beamlifetime, such amachine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a “round beam”. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.

Three-dimensional ordering of cold ion beams in a storage ring: A molecular-dynamics simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuri, Yosuke, E-mail: yuri.yosuke@jaea.go.jp

Three-dimensional (3D) ordering of a charged-particle beams circulating in a storage ring is systematically studied with a molecular-dynamics simulation code. An ion beam can exhibit a 3D ordered configuration at ultralow temperature as a result of powerful 3D laser cooling. Various unique characteristics of the ordered beams, different from those of crystalline beams, are revealed in detail, such as the single-particle motion in the transverse and longitudinal directions, and the dependence of the tune depression and the Coulomb coupling constant on the operating points.

Theory of the polarization of highly charged ions in storage rings: Production, preservation, observation and application to the search for a violation of the fundamental symmetries

NASA Astrophysics Data System (ADS)

Bondarevskaya, A.; Prozorov, A.; Labzowsky, L.; Plunien, G.; Liesen, D.; Bosch, F.

2011-10-01

Theoretical concepts for the production, preservation and control of polarized highly charged ion beams in storage rings are investigated. It is argued that hydrogen-like ions can be polarized efficiently by optical pumping of the Zeeman sublevels of ground state hyperfine levels and that the maximum achievable nuclear polarization exceeds 90%. In order to study the preservation of the polarization during the ion motion through the magnetic system of the ring, the concept of the instantaneous quantization axis is introduced. It is suggested that the employment of “Siberian snakes” may help to preserve the ion beam polarization in the ring. The control of the beam polarization can be achieved by different methods: by measuring the Stokes parameters for the emitted photons or by observing the angular dependence of the transition rates for polarized ions. The important motivation for the production of polarized ion beams is the possibility to observe parity nonconservation effects in the hyperfine-quenched transitions in helium-like highly charged ions, where these effects can reach an unprecedented high value for atomic physics. The possible observation of parity nonconservation effects connected with the nuclear anapole moment is also discussed. A method for the observation of the electric dipole moment of an electron in a storage ring with a polarized highly charged ion beam is proposed. This method allows, in principle, to improve the existing boundaries for the electric dipole moment of an electron. However, the requirements of the corresponding experiment are very stringent.

High-yield positron systems for linear colliders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clendenin, J.E.

1989-04-01

Linear colliders, such as the SLC, are among those accelerators for which a high-yield positron source operating at the repetition rate of the accelerator is desired. The SLC, having electron energies up to 50 GeV, presents the possibility of generating positron bunches with useful charge even exceeding that of the initial electron bunch. The exact positron yield to be obtained depends on the particular capture, transport and damping system employed. Using 31 GeV electrons impinging on a W-type converter phase-space at the target to the acceptance of the capture rf section, the SLC source is capable of producing, for everymore » electron, up to two positrons within the acceptance of the positron damping ring. The design of this source and the performance of the positron system as built are described. Also, future prospects and limitations for high-yield positron systems are discussed. 11 refs., 5 figs., 3 tabs.« less

The Effects of Space-Charge on the Dynamics of the Ion Booster in the Jefferson Lab EIC (JLEIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogacz, Alex; Nissen, Edward

Optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime is proposed. This study is motivated by the ultra-high luminosity promised by the JLEIC accelerator complex, which poses several beam dynamics and lattice design challenges for its individual components. We examine the effects of space charge on the dynamics of the booster synchrotron for the proposed JLEIC electron ion collider. This booster will inject and accumulate protons and heavy ions at an energy of 280 MeV and then engage in a process of acceleration and electron cooling to bring it to its extraction energy of 8more » GeV. This would then be sent into the ion collider ring part of JLEIC. In order to examine the effects of space charge on the dynamics of this process we use the software SYNERGIA.« less

Coupling tree rings and eddy covariance to estimate long-term above and belowground carbon storage at the stand level

NASA Astrophysics Data System (ADS)

Dye, A.; Alexander, M. R.; Bishop, D.; Pederson, N.; Hessl, A. E.

2016-12-01

Storage of carbon in terrestrial plants and soils directly reduces atmospheric carbon concentration, and it is thereby imperative to improve our understanding of where carbon is being stored and released in an ecosystem and how storages and releases are changing over time. At data-rich sites, coupling alternative measurements of carbon flux can improve this understanding. Here, we present a methodology to inversely model stand-level net storage and release of above- and belowground carbon over a period of 1-2 decades using co-located tree-ring plots and eddy covariance towers at three eastern U.S. forests. We reconstructed annual aboveground wood production (aNPP) from tree rings collected near eddy covariance towers. We compared our aNPP reconstructions with annual tower NEE to address whether interannual variations are correlated. Despite modest correlation, we observed magnitude differences between both records that vary annually. We interpret these differences as indicative of changes in belowground carbon storage, i.e. an aNPP:NEE ratio > 1 indicates a net release of belowground carbon and a ratio < 1 a net storage of belowground carbon. For this interpretation, we assume the following: a) carbon not directed to above or belowground pools is insignificant, b) carbon not stored above ground is stored below ground, and c) mature trees do not add to a storage pool at a higher level every year. While the offset between biometric aNPP and tower NEE could partially be attributed to the diversion of assimilated carbon to nonstructural carbohydrates instead of growth, we argue that this becomes a less important factor over longer time scales in a mature tree. Our approach does not quantify belowground NPP or allocation, but we present a method for estimating belowground carbon storage and release at the stand level, an otherwise difficult task at this scale due to heterogeneity across the stand.

Hardy Objects in Saturn F Ring

NASA Image and Video Library

2017-02-24

As NASA's Cassini spacecraft continues its weekly ring-grazing orbits, diving just past the outside of Saturn F ring, it is tracking several small, persistent objects there. These images show two such objects that Cassini originally detected in spring 2016, as the spacecraft transitioned from more equatorial orbits to orbits at increasingly high inclination about the planet's equator. Imaging team members studying these objects gave them the informal designations F16QA (right image) and F16QB (left image). The researchers have observed that objects such as these occasionally crash through the F ring's bright core, producing spectacular collisional structures.While these objects may be mostly loose agglomerations of tiny ring particles, scientists suspect that small, fairly solid bodies lurk within each object, given that they have survived several collisions with the ring since their discovery. The faint retinue of dust around them is likely the result of the most recent collision each underwent before these images were obtained. The researchers think these objects originally form as loose clumps in the F ring core as a result of perturbations triggered by Saturn's moon Prometheus. . If they survive subsequent encounters with Prometheus, their orbits can evolve, eventually leading to core-crossing clumps that produce spectacular features, even though they collide with the ring at low speeds. The images were obtained using the Cassini spacecraft narrow-angle camera on Feb. 5, 2017, at a distance of 610,000 miles (982,000 kilometers, left image) and 556,000 miles (894,000 kilometers, right image) from the F ring. Image scale is about 4 miles (6 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21432

Baroclinic flows, transports, and kinematic properties in a cyclonic-anticyclonic-cyclonic ring triad in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Vidal, VíCtor M. V.; Vidal, Francisco V.; HernáNdez, Abel F.; Meza, Eustorgio; PéRez-Molero, José M.

1994-04-01

During October-November 1986 the baroclinic circulation of the central and western Gulf of Mexico was dominated by an anticyclonic ring that was being bisected by two north and south flanking cyclonic rings. The baroclinic circulation revealed a well-defined cyclonic-anticyclonic-cyclonic triad system. The anticyclone's collision against the western gulf continental slope at 22.5°N, 97°W originated the north and south flanking cyclonic rings. The weakening of the anticyclone's relative vorticity, during the collision, was compensated by along-shelf north (26 cm s-1) and south (58 cm s-1) jet currents and by the anticyclone's flanking water mass's gain of cyclonic vorticity from lateral shear contributed by east (56 cm s-1) and west (42 cm s-1) current jets with individual mass transports of ˜18 Sv. Within the 0-1000 and 0-500 dbar layers and across 96°W the magnitudes of the colliding westward transports were 17.80 and 8.59 Sv, respectively. These corresponding transports were 85 and 94% balanced by along-shelf jet currents north and south of the anticyclone's collision zone. This indicates that only minor amounts (<15%) of the anticyclone's colliding westward transports might have flowed into the western gulf's continental shelf water mass or else they sank into deeper water along the continental slope during the anticyclone's collision event. The resultant effect of the coupled interaction between the anticyclone and the cyclonic pair was the surging of the water mass in the cyclones and its sinking in the anticyclone. This mechanism controlled the magnitude, direction, location of vertical advection, and transfer of kinetic energy from the upper to the deeper water layers. Our vertical transport estimates through the 1000-m-depth surface revealed a net vertical descending transport of 0.4 Sv for the ring triad system. This mass flux occurred primordially within the south central gulf region and most likely constituted a principal mechanism that propelled the gulf's deep horizontal circulation. The volume renewal time is ˜5 years for the ring triad system within 0-1000 dbar. The volume renewal time for the gulf's deep water layer (2000-3000 dbar), estimated as a function of its horizontal outflowing mass flux (1.96 Sv), is of the same order of magnitude and reveals that the deeper layer of the Gulf of Mexico is as well ventilated as its upper layer (0-1000 dbar). The ring triad's surface kinematic properties were derived from the sea surface baroclinic circulation field referenced to 500 dbar. Within this layer, individual ring geometries were conserved. Maximum tangential ring velocities were 60 and 58 cm s-1, for the north and south cyclones respectively, and 30 cm s-1 for the anticyclone. The corresponding periods of revolution were 16, 19, and 26 days, and vertical velocities calculated at the rings' peripheries, where maximum horizontal divergence was encountered, were 1.5, 1.0, and -1.0 m d-1.

Maury Goodman

Science.gov Websites

the 29th International Cosmic Ray Conference, Pune India, August 10, 2005 Reactor Searches for Theta Rings, Bombay India, August 2, 2005 NOvA Presentation at the Workshop on Physics of Atmospheric Neutrinos and Neutrinos from Muon Storage Rings, Bombay India, August 2, 2005 The Double Chooz Double Fast

Reinterpreting the Sharp Edges of Planetary Rings

NASA Astrophysics Data System (ADS)

Rimlinger, Thomas; Hamilton, Douglas P.; Hahn, Joseph M.

2016-10-01

Narrow ringlets are found throughout the Solar System and are typically 1-100 km wide. Angular momentum, L, is the key to understanding how narrow rings remain confined; L2 ∝ a(1 - e2) for semimajor axis a and eccentricity e. In a circular ring, L conservation demands that the ring quickly spread apart when some colliding particles lose energy while others gain it. By contrast, in an eccentric ring, energy loss and the associated decay of the average semi-major axes can be offset by a decrease in the average eccentricity. We argue that a ring's lifetime can be greatly extended if particles arrange themselves in this way (Borderies et al. 1984). The key difference of our model, however, is that rings need not be shepherded and can confine themselves provided they are sufficiently eccentric. Satellites merely extend the rings' lifespans by pumping up their eccentricities.This confinement mechanism can explain the existence and longevity of narrow ringlets in a variety of contexts. Saturn's Titan ringlet, which is quite circular, may nevertheless be able to confine itself indefinitely if its eccentricity decay is balanced by the increase from the resonance with Titan. Preliminary simulations presented by Rimlinger et al. at this year's DDA Conference have verified that this ring can self-confine even in the absence of any satellite; we update these findings with new results that include the effects of Titan. Furthermore, Mimas' resonance with the edge of the B ring may excite its higher order modes to similar effect. We update the findings of Hahn and Spitale (2013), who used artificial forces to confine the B ring's edge, and suggest that with a suitable viscosity and density, no such forces will be needed to keep the edge sharp. Finally, a ring that is "born" with a sufficiently high eccentricity may live for hundreds of millions or even billions of years in isolation if the rate of decay is slow enough. We present simulations exploring such a scenario.

Sc-Decorated Porous Graphene for High-Capacity Hydrogen Storage: First-Principles Calculations.

PubMed

Chen, Yuhong; Wang, Jing; Yuan, Lihua; Zhang, Meiling; Zhang, Cairong

2017-08-02

The generalized gradient approximation (GGA) function based on density functional theory is adopted to investigate the optimized geometrical structure, electron structure and hydrogen storage performance of Sc modified porous graphene (PG). It is found that the carbon ring center is the most stable adsorbed position for a single Sc atom on PG, and the maximum number of adsorbed H₂ molecules is four with the average adsorption energy of -0.429 eV/H₂. By adding a second Sc atom on the other side of the system, the hydrogen storage capacity of the system can be improved effectively. Two Sc atoms located on opposite sides of the PG carbon ring center hole is the most suitable hydrogen storage structure, and the hydrogen storage capacity reach a maximum 9.09 wt % at the average adsorption energy of -0.296 eV/H₂. The adsorption of H₂ molecules in the PG system is mainly attributed to orbital hybridization among H, Sc, and C atoms, and Coulomb attraction between negatively charged H₂ molecules and positively charged Sc atoms.

Sc-Decorated Porous Graphene for High-Capacity Hydrogen Storage: First-Principles Calculations

PubMed Central

Chen, Yuhong; Wang, Jing; Yuan, Lihua; Zhang, Meiling

2017-01-01

The generalized gradient approximation (GGA) function based on density functional theory is adopted to investigate the optimized geometrical structure, electron structure and hydrogen storage performance of Sc modified porous graphene (PG). It is found that the carbon ring center is the most stable adsorbed position for a single Sc atom on PG, and the maximum number of adsorbed H2 molecules is four with the average adsorption energy of −0.429 eV/H2. By adding a second Sc atom on the other side of the system, the hydrogen storage capacity of the system can be improved effectively. Two Sc atoms located on opposite sides of the PG carbon ring center hole is the most suitable hydrogen storage structure, and the hydrogen storage capacity reach a maximum 9.09 wt % at the average adsorption energy of −0.296 eV/H2. The adsorption of H2 molecules in the PG system is mainly attributed to orbital hybridization among H, Sc, and C atoms, and Coulomb attraction between negatively charged H2 molecules and positively charged Sc atoms. PMID:28767084

Stem water storage in five coexisting temperate broad-leaved tree species: significance, temporal dynamics and dependence on tree functional traits.

PubMed

Köcher, Paul; Horna, Viviana; Leuschner, Christoph

2013-08-01

The functional role of internal water storage is increasingly well understood in tropical trees and conifers, while temperate broad-leaved trees have only rarely been studied. We examined the magnitude and dynamics of the use of stem water reserves for transpiration in five coexisting temperate broad-leaved trees with largely different morphology and physiology (genera Fagus, Fraxinus, Tilia, Carpinus and Acer). We expected that differences in water storage patterns would mostly reflect species differences in wood anatomy (ring vs. diffuse-porous) and wood density. Sap flux density was recorded synchronously at five positions along the root-to-branch flow path of mature trees (roots, three stem positions and branches) with high temporal resolution (2 min) and related to stem radius changes recorded with electronic point dendrometers. The daily amount of stored stem water withdrawn for transpiration was estimated by comparing the integrated flow at stem base and stem top. The temporal coincidence of flows at different positions and apparent time lags were examined by cross-correlation analysis. Our results confirm that internal water stores play an important role in the four diffuse-porous species with estimated 5-12 kg day(-1) being withdrawn on average in 25-28 m tall trees representing 10-22% of daily transpiration; in contrast, only 0.5-2.0 kg day(-1) was withdrawn in ring-porous Fraxinus. Wood density had a large influence on storage; sapwood area (diffuse- vs. ring-porous) may be another influential factor but its effect was not significant. Across the five species, the length of the time lag in flow at stem top and stem base was positively related to the size of stem storage. The stem stores were mostly exhausted when the soil matrix potential dropped below -0.1 MPa and daily mean vapor pressure deficit exceeded 3-5 hPa. We conclude that stem storage is an important factor improving the water balance of diffuse-porous temperate broad-leaved trees in moist periods, while it may be of low relevance in dry periods and in ring-porous species.

Compensation of the long-range beam-beam interactions as a path towards new configurations for the high luminosity LHC

DOE PAGES

Fartoukh, Stéphane; Valishev, Alexander; Papaphilippou, Yannis; ...

2015-12-01

Colliding bunch trains in a circular collider demands a certain crossing angle in order to separate the two beams transversely after the collision. The magnitude of this crossing angle is a complicated function of the bunch charge, the number of long-range beam-beam interactions, of β* and type of optics (flat or round), and possible compensation or additive effects between several low-β insertions in the ring depending on the orientation of the crossing plane at each interaction point. About 15 years ago, the use of current bearing wires was proposed at CERN in order to mitigate the long-range beam-beam effects [J.P. Koutchouk,more » CERN Report No. LHC-Project-Note 223, 2000], therefore offering the possibility to minimize the crossing angle with all the beneficial effects this might have: on the luminosity performance by reducing the need for crab-cavities or lowering their voltage, on the required aperture of the final focus magnets, on the strength of the orbit corrector involved in the crossing bumps, and finally on the heat load and radiation dose deposited in the final focus quadrupoles. In this paper, a semianalytical approach is developed for the compensation of the long-range beam-beam interactions with current wires. This reveals the possibility of achieving optimal correction through a careful adjustment of the aspect ratio of the β functions at the wire position. We consider the baseline luminosity upgrade plan of the Large Hadron Collider (HL-LHC project), and compare it to alternative scenarios, or so-called ''configurations,'' where modifications are applied to optics, crossing angle, or orientation of the crossing plane in the two low-β insertions of the ring. Furthermore, for all these configurations, the beneficial impact of beam-beam compensation devices is then demonstrated on the tune footprint, the dynamical aperture, and/or the frequency map analysis of the nonlinear beam dynamics as the main figures of merit.« less

Field Modeling, Symplectic Tracking, and Spin Decoherence for EDM and Muon $$g\\textrm{-}2$$ Lattices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valetov, Eremey Vladimirovich

2017-01-01

While the first particle accelerators were electrostatic machines, and several electrostatic storage rings were subsequently commissioned and operated, electrostatic storage rings pose a number of challenges. Unlike motion in the magnetic field, where particle energy remains constant, particle energy generally changes in electrostatic elements. Conservation of energy in an electrostatic element is, in practice, only approximate, and it requires careful and accurate design, manufacturing, installation, and operational use. Electrostatic deflectors require relatively high electrostatic fields, tend to introduce nonlinear aberrations of all orders, and are more challenging to manufacture than homogeneous magnetic dipoles. Accordingly, magnetic storage rings are overwhelmingly prevalent.more » The search for electric dipole moments (EDMs) of fundamental particles is of key importance in the study of C and CP violations and their sources. C and CP violations are part of the Sakharov conditions that explain the matter–antimatter asymmetry in the universe. Determining the source of CP violations would provide valuable empirical insight for beyond-Standard-Model physics. EDMs of fundamental particles have not to this date been experimentally observed. The search for fundamental particle EDMs has narrowed the target search region; however, an EDM signal is yet to be discovered. In 2008, Brookhaven National Laboratory (BNL) had proposed the frozen spin (FS) concept for the search of a deuteron EDM. The FS concept envisions launching deuterons through a storage ring with combined electrostatic and magnetic fields. The electrostatic and magnetic fields are in a proportion that would, without an EDM, freeze the deuteron’s spin along its momentum as the deuteron moves around the lattice. The radial electrostatic field would result in a torque on the spin vector, proportional to a deuteron EDM, rotating the spin vector out of the midplane.« less

Storing keV negative ions for an hour: the lifetime of the metastable ^(2)P((1/2)^(o)) level in ^(32)S^(-).

PubMed

Bäckström, E; Hanstorp, D; Hole, O M; Kaminska, M; Nascimento, R F; Blom, M; Björkhage, M; Källberg, A; Löfgren, P; Reinhed, P; Rosén, S; Simonsson, A; Thomas, R D; Mannervik, S; Schmidt, H T; Cederquist, H

2015-04-10

We use a novel electrostatic ion storage ring to measure the radiative lifetime of the upper level in the 3p^{5} ^{2}P_{1/2}^{o}→3p^{5} ^{2}P_{3/2}^{o} spontaneous radiative decay in ^{32}S^{-} to be 503±54  sec. This is by orders of magnitude the longest lifetime ever measured in a negatively charged ion. Cryogenic cooling of the storage ring gives a residual-gas pressure of a few times 10^{-14} mbar at 13 K and storage of 10 keV sulfur anions for more than an hour. Our experimental results differ by 1.3σ from the only available theoretical prediction [P. Andersson et al., Phys. Rev. A 73, 032705 (2006)].

Fermilab 4.3-MeV Electron Cooler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagaitsev, Sergei; Prost, Lionel; Shemyakin, Alexander

The Recycler Electron Cooler (REC) was the first cooler working at a relativistic energy (gamma = 9.5). It was successfully developed in 1995-2004 and was in operation at Fermilab in 2005-2011, providing cooling of antiprotons in the Recycler ring. After introducing the physics of electron cooling and the REC system, this paper describes measurements carried out to tune the electron beam and optimize its cooling properties. In particular, we discuss the cooling strategy adopted for maximizing the collider integrated luminosity.

The Large Hadron Collider (LHC): The Energy Frontier

NASA Astrophysics Data System (ADS)

Brianti, Giorgio; Jenni, Peter

The following sections are included: * Introduction * Superconducting Magnets: Powerful, Precise, Plentiful * LHC Cryogenics: Quantum Fluids at Work * Current Leads: High Temperature Superconductors to the Fore * A Pumping Vacuum Chamber: Ultimate Simplicity * Vertex Detectors at LHC: In Search of Beauty * Large Silicon Trackers: Fast, Precise, Efficient * Two Approaches to High Resolution Electromagnetic Calorimetry * Multigap Resistive Plate Chamber: Chronometry of Particles * The LHCb RICH: The Lord of the Cherenkov Rings * Signal Processing: Taming the LHC Data Avalanche * Giant Magnets for Giant Detectors

CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

NASA Astrophysics Data System (ADS)

Najafi, M. A.; Dillmann, I.; Bosch, F.; Faestermann, T.; Gao, B.; Gernhäuser, R.; Kozhuharov, C.; Litvinov, S. A.; Litvinov, Yu. A.; Maier, L.; Nolden, F.; Popp, U.; Sanjari, M. S.; Spillmann, U.; Steck, M.; Stöhlker, T.; Weick, H.

2016-11-01

A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE / E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

Saturation of the laser-induced narrowband coherent synchrotron radiation process: Experimental observation at a storage ring

NASA Astrophysics Data System (ADS)

Hosaka, M.; Yamamoto, N.; Takashima, Y.; Szwaj, C.; Le Parquier, M.; Evain, C.; Bielawski, S.; Adachi, M.; Zen, H.; Tanikawa, T.; Kimura, S.; Katoh, M.; Shimada, M.; Takahashi, T.

2013-02-01

We study the efficiency limitation affecting laser-induced coherent synchrotron radiation (CSR) at high laser power. Experiments are made on the UVSOR-II storage ring in conditions of narrowband terahertz CSR emission. While, at moderate power, CSR power increases quadratically with laser power, a noticeable decrease in efficiency and eventually a decrease in CSR power is observed experimentally at high power. Details of the underlying process are analyzed numerically. As the saturation effect depends almost instantaneously on the laser intensity, the saturation occurs locally in longitudinal space. This has important consequences on the modulation pattern induced on the electron bunch.

Progress on the Design of the Storage Ring Vacuum System for the Advanced Photon Source Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillwell, B.; Billett, B.; Brajuskovic, B.

2017-06-20

Recent work on the design of the storage ring vacuum system for the Advanced Photon Source Upgrade project (APS-U) includes: revising the vacuum system design to accommodate a new lattice with reverse bend magnets, modifying the designs of vacuum chambers in the FODO sections for more intense incident synchrotron radiation power, modifying the design of rf-shielding bellows liners for better performance and reliability, modifying photon absorber designs to make better use of available space, and integrated planning of components needed in the injection, extraction and rf cavity straight sections. An overview of progress in these areas is presented.

Development and operating experience of a short-period superconducting undulator at the Advanced Photon Source

DOE PAGES

Ivanyushenkov, Y.; Harkay, K.; Abliz, M.; ...

2015-04-01

In this study, a decade-long effort at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) on development of superconducting undulators culminated in December 2012 with the installation of the first superconducting undulator “SCU0” into Sector 6 of the APS storage ring. The device was commissioned in January 2013 and has been in user operation since. This paper presents the magnetic and cryogenic design of the SCU0 together with the results of stand-alone cold tests. The initial commissioning and characterization of SCU0 as well as its operating experience in the APS storage ring are described.

Measurement of Tensor Analyzing Powers for Elastic Electron Scattering from a Polarized 2H Target Internal to a Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Ferro-Luzzi; M. Bouwhuis; E. Passchier

1996-09-23

We report an absolute measurement of the tensor analyzing powers T20 and T22 in elastic electron-deuteron scattering at a momentum transfer of 1.6 fm{sup -1}. The novel approach of this measurement is the use of a tensor polarized 2H target internal to an electron storage ring, with in situ measurement of the polarization of the target gas. Scattered electrons and recoil deuterons were detected in coincidence with two large acceptance nonmagnetic detectors. The techniques demonstrated have broad applicability to further measurements of spin-dependent electron scattering.

Broadband impedance calculations and single bunch instabilities estimations of of the HLS-II storage ring

NASA Astrophysics Data System (ADS)

Zhang, Qing-Kun; Wang, Lin; Li, Wei-Min; Gao, Wei-Wei

2015-12-01

The upgrade project of the Hefei Light Source storage ring is under way. In this paper, the broadband impedances of resistive wall and coated ceramic vacuum chamber are calculated using the analytic formula, and the wake fields and impedances of other designed vacuum chambers are simulated by CST code, and then a broadband impedance model is obtained. Using the theoretical formula, longitudinal and transverse single bunch instabilities are discussed. With the carefully-designed vacuum chamber, we find that the thresholds of the beam instabilities are higher than the beam current goal. Supported by Natural Science Foundation of China (11175182, 11175180)

Transparent lattice characterization with gated turn-by-turn data of diagnostic bunch train

NASA Astrophysics Data System (ADS)

Li, Yongjun; Cheng, Weixing; Ha, Kiman; Rainer, Robert

2017-11-01

Methods of characterization of a storage ring's lattice have traditionally been intrusive to routine operations. More importantly, the lattice seen by particles can drift with the beam current due to collective effects. To circumvent this, we have developed a novel approach for dynamically characterizing a storage ring's lattice that is transparent to operations. Our approach adopts a dedicated filling pattern which has a short, separate diagnostic bunch train (DBT). Through the use of a bunch-by-bunch feedback system, the DBT can be selectively excited on demand. Gated functionality of a beam position monitor system is capable of collecting turn-by-turn data of the DBT, from which the lattice can then be characterized after excitation. As the DBT comprises only about one percent of the total operational bunches, the effects of its excitation are negligible to users. This approach allows us to localize the distributed quadrupolar wakefields generated in the storage ring vacuum chamber during beam accumulation. While effectively transparent to operations, our approach enables us to dynamically control the beta beat and phase beat, and unobtrusively optimize performance of the National Synchrotron Light Source-II accelerator during routine operations.

Upgrade of BPM Electronics for the SPring-8 Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasaki, Shigeki; Fujita, Takahiro; Shoji, Masazumi

2006-11-20

SPring-8, a 3rd generation synchrotron light source, has operated since 1997. Improvement of BPM performance is required as a part of upgrading activities of the storage ring as a light source. We have developed new electronics circuits for signal processing of the storage ring BPM, with target performance of sub-{mu}m range resolution with sufficiently fast measurement speed and good long-term stability. A set of the new circuits consists of multiplexers, an RF amplifier, a mixer, an IF amplifier, and a local oscillator for analog signal processing. The IF amplifier outputs are sampled with 16-bit 2-MSPS ADC on ADC boards andmore » the data are sent to a DSP board. The sampled data are processed and converted to position information in the DSP. A multiplexing method was employed to have a better stability of the performance by cancellation of variation common to each channel. Evaluation of the performance by using a prototype shows that position resolution well into the sub-{mu}m range has been achieved with a bandwidth of 1 kHz, and long-term stability of within 1 {mu}m has also been achieved.« less

Transparent lattice characterization with gated turn-by-turn data of diagnostic bunch train

DOE PAGES

Li, Yongjun; Cheng, Weixing; Ha, Kiman; ...

2017-11-21

Methods of characterization of a storage ring's lattice have traditionally been intrusive to routine operations. More importantly, the lattice seen by particles can drift with the beam current due to collective effects. To circumvent this, we have developed a novel approach for dynamically characterizing a storage ring's lattice that is transparent to operations. Our approach adopts a dedicated filling pattern which has a short, separate Diagnostic Bunch-Train (DBT). Through the use of a bunch-by-bunch feedback system, the DBT can be selectively excited on-demand. Gated functionality of a beam position monitor system is capable of collecting turn-by-turn data of the DBT,more » from which the lattice can then be characterized after excitation. As the DBT comprises only about one percent of the total operational bunches, the effects of its excitation are negligible to users. Therefore, this approach allows us to localize the distributed quadrupolar wake fields generated in the storage ring vacuum chamber during beam accumulation. While effectively transparent to operations, our approach enables us to dynamically control the beta-beat and phase-beat, and unobtrusively optimize performance of National Synchrotron Light Source-II accelerator during routine operations.« less

Synchrotron oscillation effects on an rf-solenoid spin resonance

NASA Astrophysics Data System (ADS)

Benati, P.; Chiladze, D.; Dietrich, J.; Gaisser, M.; Gebel, R.; Guidoboni, G.; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Kulessa, P.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Öllers, D.; Pesce, A.; Polyanskiy, A.; Prasuhn, D.; Rathmann, F.; Semertzidis, Y. K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Valdau, Yu.; Weidemann, Ch.; Wüstner, P.

2012-12-01

New measurements are reported for the time dependence of the vertical polarization of a 0.97GeV/c deuteron beam circulating in a storage ring and perturbed by an rf solenoid. The storage ring is the cooler synchrotron (COSY) located at the Forschungszentrum Jülich. The beam polarization was measured continuously using a 1.5 cm thick carbon target located at the edge of the circulating deuteron beam and the scintillators of the EDDA detector. An rf solenoid mounted on the ring was used to generate fields at and near the frequency of the 1-Gγ spin resonance. Measurements were made of the vertical beam polarization as a function of time with the operation of the rf solenoid in either fixed or continuously variable frequency mode. Using rf-solenoid strengths as large as 2.66×10-5revolutions/turn, slow oscillations (˜1Hz) were observed in the vertical beam polarization. When the circulating beam was continuously electron cooled, these oscillations completely reversed the polarization and showed no sign of diminishing in amplitude. But for the uncooled beam, the oscillation amplitude was damped to nearly zero within a few seconds. A simple spin-tracking model without the details of the COSY ring lattice was successful in reproducing these oscillations and demonstrating the sensitivity of the damping to the magnitude of the synchrotron motion of the beam particles. The model demonstrates that the characteristic features of measurements made in the presence of large synchrotron oscillations are distinct from the features of such measurements when made off resonance. These data were collected in preparation for a study of the spin coherence time, a beam property that needs to become long to enable a search for an electric dipole moment using a storage ring.

Optimising LAN access to grid enabled storage elements

NASA Astrophysics Data System (ADS)

Stewart, G. A.; Cowan, G. A.; Dunne, B.; Elwell, A.; Millar, A. P.

2008-07-01

When operational, the Large Hadron Collider experiments at CERN will collect tens of petabytes of physics data per year. The worldwide LHC computing grid (WLCG) will distribute this data to over two hundred Tier-1 and Tier-2 computing centres, enabling particle physicists around the globe to access the data for analysis. Although different middleware solutions exist for effective management of storage systems at collaborating institutes, the patterns of access envisaged for Tier-2s fall into two distinct categories. The first involves bulk transfer of data between different Grid storage elements using protocols such as GridFTP. This data movement will principally involve writing ESD and AOD files into Tier-2 storage. Secondly, once datasets are stored at a Tier-2, physics analysis jobs will read the data from the local SE. Such jobs require a POSIX-like interface to the storage so that individual physics events can be extracted. In this paper we consider the performance of POSIX-like access to files held in Disk Pool Manager (DPM) storage elements, a popular lightweight SRM storage manager from EGEE.

In-space inertial energy storage design

NASA Technical Reports Server (NTRS)

Studer, P. A.; Evans, H. E.

1981-01-01

Flywheel energy storage is a means of significantly improving the performance of space power systems. Two study contracts have been completed to investigate the merits of a magnetically suspended, ironless armature, ring rotor 'Mechanical Capacitor' design. The design of a suitable energy storage system is evaluated, taking into account baseline requirements, the motor generator, details regarding the suspension design, power conditioning, the rotor, and an example design. It appears on the basis of this evaluation that the inertial (flywheel) energy storage design is feasible.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L; Sexton, James C

2013-10-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L.; Sexton, James C.

2013-01-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

15. DETAILED VIEW OF ENRICHED URANIUM STORAGE TANK. THE ADDITION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. DETAILED VIEW OF ENRICHED URANIUM STORAGE TANK. THE ADDITION OF THE GLASS RINGS SHOWN AT THE TOP OF THE TANK HELPS PREVENT THE URANIUM FROM REACHING CRITICALITY LIMITS. (4/12/62) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

A permanent-magnet rotor for a high-temperature superconducting bearing

NASA Astrophysics Data System (ADS)

Mulcahy, T. M.; Hull, J. R.; Uherka, K. L.; Abboud, R. G.; Wise, J. H.; Carnegie, D. W.

1995-06-01

Design, fabrication, and performance, of a 1/3-m dia., 10-kg flywheel rotor with only one bearing is discussed. To achieve low-loss energy storage, the rotor's segmented-ring permanent-magnet (PM) is optimized for levitation and circumferential homogeneity. The magnet's carbon composite bands enable practical energy storage.

Radiation protection and environmental management at the relativistic heavy ion collider.

PubMed

Musolino, S V; Briggs, S L; Stevens, A J

2001-01-01

The Relativistic Heavy Ion Collider (RHIC) is a high energy hadron accelerator built to study basic nuclear physics. It consists of two counter-rotating beams of fully stripped gold ions that are accelerated in two rings to an energy of 100 GeV/nucleon or protons at 250 GeV/c. The beams can be stored for a period of five to ten hours and brought into collision for experiments during that time. The first major physics objective is to recreate a state of matter, the quark-gluon plasma, that has been predicted to have existed at a short time after the creation of the universe. Because there are only a few other high energy particle accelerators like RHIC in the world, the rules promulgated in the US Code of Federal Regulations under the Atomic Energy Act, State regulations, or international guidance documents do not cover prompt radiation from accelerators to govern directly the design and operation of a superconducting collider. Special design criteria for prompt radiation were developed to provide guidance tor the design of radiation shielding. Environmental Management at RHIC is accomplished through the ISO 14001 Environmental Management System. The applicability, benefits, and implementation of ISO 14001 within the framework of a large research accelerator complex are discussed in the paper.

Conceptual design of hollow electron lenses for beam halo control in the Large Hadron Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stancari, Giulio; Previtali, Valentina; Valishev, Alexander

Collimation with hollow electron beams is a technique for halo control in high-power hadron beams. It is based on an electron beam (possibly pulsed or modulated in intensity) guided by strong axial magnetic fields which overlaps with the circulating beam in a short section of the ring. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. We are proposing a conceptual design for applying this technique to the Large Hadron Collider at CERN. A prototype hollow electron gun for the LHC was built and tested. Themore » expected performance of the hollow electron beam collimator was based on Tevatron experiments and on numerical tracking simulations. Halo removal rates and enhancements of halo diffusivity were estimated as a function of beam and lattice parameters. Proton beam core lifetimes and emittance growth rates were checked to ensure that undesired effects were suppressed. Hardware specifications were based on the Tevatron devices and on preliminary engineering integration studies in the LHC machine. Required resources and a possible timeline were also outlined, together with a brief discussion of alternative halo-removal schemes and of other possible uses of electron lenses to improve the performance of the LHC.« less

Very large hadron collider (VLHC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1998-09-01

A VLHC informal study group started to come together at Fermilab in the fall of 1995 and at the 1996 Snowmass Study the parameters of this machine took form. The VLHC as now conceived would be a 100 TeV hadron collider. It would use the Fermilab Main Injector (now nearing completion) to inject protons at 150 GeV into a new 3 TeV Booster and then into a superconducting pp collider ring producing 100 TeV c.m. interactions. A luminosity of {approximately}10{sup 34} cm{sup -2}s{sup -1} is planned. Our plans were presented to the Subpanel on the Planning for the Future ofmore » US High- Energy Physics (the successor to the Drell committee) and in February 1998 their report stated ``The Subpanel recommends an expanded program of R&D on cost reduction strategies, enabling technologies, and accelerator physics issues for a VLHC. These efforts should be coordinated across laboratory and university groups with the aim of identifying design concepts for an economically and technically viable facility`` The coordination has been started with the inclusion of physicists from Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL), and Cornell University. Clearly, this collaboration must expanded internationally as well as nationally. The phrase ``economically and technically viable facility`` presents the real challenge.« less

Energy storage apparatus

NASA Technical Reports Server (NTRS)

Studer, P. A.; Evans, H. E. (Inventor)

1978-01-01

A high efficiency, flywheel type energy storage device which comprises an electronically commutated d.c. motor/generator unit having a massive flywheel rotor magnetically suspended around a ring shaped stator is presented. During periods of low energy demand, the storage devices were operated as a motor, and the flywheel motor was brought up to operating speed. Energy was drawn from the device functioning as a generator as the flywheel rotor rotated during high energy demand periods.

Overview of a flywheel stack energy storage system

NASA Technical Reports Server (NTRS)

Kirk, James A.; Anand, Davinder K.

1988-01-01

The concept of storing electrical energy in rotating flywheels provides an attractive substitute to batteries. To realize these advantages the critical technologies of rotor design, composite materials, magnetic suspension, and high efficiency motor/generators are reviewed in this paper. The magnetically suspended flywheel energy storage system, currently under development at the University of Maryland, consisting of a family of interference assembled rings, is presented as an integrated solution for energy storage.

Space-charge-sustained microbunch structure in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Danilov, V.; Holmes, J.; Macek, R.

2004-09-01

We present experimental data from the Los Alamos Proton Storage Ring (PSR) showing long-lived linac microbunch structure during beam storage with no rf bunching. Analysis of the experimental data and particle-in-cell simulations of the experiments indicate that space charge, coupled with energy spread effects, is responsible for the sustained microbunch structure. The simulated longitudinal phase space of the beam reveals a well-defined separatrix in the phase space between linac microbunches, with particles executing unbounded motion outside of the separatrix. We show that the longitudinal phase space of the beam was near steady state during the PSR experiments, such that the separatrix persisted for long periods of time. Our simulations indicate that the steady state is very sensitive to the experimental conditions. Finally, we solve the steady-state problem in an analytic, self-consistent fashion for a set of periodic longitudinal space-charge potentials.

Computational Analysis on Performance of Thermal Energy Storage (TES) Diffuser

NASA Astrophysics Data System (ADS)

Adib, M. A. H. M.; Adnan, F.; Ismail, A. R.; Kardigama, K.; Salaam, H. A.; Ahmad, Z.; Johari, N. H.; Anuar, Z.; Azmi, N. S. N.

2012-09-01

Application of thermal energy storage (TES) system reduces cost and energy consumption. The performance of the overall operation is affected by diffuser design. In this study, computational analysis is used to determine the thermocline thickness. Three dimensional simulations with different tank height-to-diameter ratio (HD), diffuser opening and the effect of difference number of diffuser holes are investigated. Medium HD tanks simulations with double ring octagonal diffuser show good thermocline behavior and clear distinction between warm and cold water. The result show, the best performance of thermocline thickness during 50% time charging occur in medium tank with height-to-diameter ratio of 4.0 and double ring octagonal diffuser with 48 holes (9mm opening ~ 60%) acceptable compared to diffuser with 6mm ~ 40% and 12mm ~ 80% opening. The conclusion is computational analysis method are very useful in the study on performance of thermal energy storage (TES).

The Hadron Blind Ring Imaging Cherenkov Detector

NASA Astrophysics Data System (ADS)

Blatnik, Marie; Zajac, Stephanie; Hemmick, Tom

2013-10-01

Heavy Ion Collisions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab have hinted at the existence of a new form of matter at high gluon density, the Color Glass Condensate. High energy electron scattering off of nuclei, focusing on the low-x components of the nuclear wave function, will definitively measure this state of matter. However, when a nucleus contributes a low x parton, the reaction products are highly focused in the electron-going direction and have large momentum in the lab system. High-momentum particle identification is particularly challenging. A particle is identifiable by its mass, but tracking algorithms only yield a particle's momentum based on its track's curvature. The particle's velocity is needed to identify the particle. A ring-imaging Cerenkov detector is being developed for the forward angle particle identification from the technological advancements of PHENIX's Hadron-Blind Detector (HBD), which uses Gas Electron Multipliers (GEMs) and pixelated pad planes to detect Cerenkov photons. The new HBD will focus the Cerenkov photons into a ring to determine the parent particle's velocity. Results from the pad plane simulations, construction tests, and test beam run will be presented.

Chandra Reveals Rich Oxygen Supply

NASA Technical Reports Server (NTRS)

2003-01-01

This striking Chandra X-Ray Observatory image of supernova remnant SNR0103-72.6 reveals a nearly perfect ring about 150 light years in diameter surrounding a cloud of gas enriched in oxygen and shock-heated to millions of degrees Celsius. The ring marks the outer limits of a shock wave produced as material ejected in the supernova explosion collides with the interstellar gas. The size of the ring indicates that we see the supernova remnant as it was about 10,000 years after its progenitor star exploded. Located in the Small Magenellanic Cloud (SMC), SNR 0103-72.6 is about 190,000 light years from Earth. The x-rays take about 190,000 years to reach us from the SMC, so the supernova explosion occurred about 200,000 years ago, as measured on Earth. Scientists have know for years that oxygen and many other elements necessary for life are created in massive stars and dispersed in supernova explosions, but few remnants rich in these elements have been observed. This supernova remnant will hence become an important laboratory for studying how stars forge the elements necessary for life.

Modeling the Effects of Mirror Misalignment in a Ring Imaging Cherenkov Detector

NASA Astrophysics Data System (ADS)

Hitchcock, Tawanda; Harton, Austin; Garcia, Edmundo

2012-03-01

The Very High Momentum Particle Identification Detector (VHMPID) has been proposed for the ALICE experiment at the Large Hadron Collider (LHC). This detector upgrade is considered necessary to study jet-matter interaction at high energies. The VHMPID identifies charged hadrons in the 5 GeV/c to 25 GeV/c momentum range. The Cherenkov photons emitted in the VHMPID radiator are collected by spherical mirrors and focused onto a photo-detector plane forming a ring image. The radius of this ring is related to the Cherenkov angle, this information coupled with the particle momentum allows the particle identification. A major issue in the RICH detector is that environmental conditions can cause movements in mirror position. In addition, chromatic dispersion causes the refractive index to shift, altering the Cherenkov angle. We are modeling a twelve mirror RICH detector taking into account the effects of mirror misalignment and chromatic dispersion using a commercial optical software package. This will include quantifying the effects of both rotational and translational mirror misalignment for the initial assembly of the module and later on particle identification.

PEP as a synchrotron radiation source (invited)

NASA Astrophysics Data System (ADS)

Bienenstock, A.; Brown, G.; Wiedemann, H.; Winick, H.

1989-07-01

The 16-GeV storage ring PEP has characteristics which enable it to operate in modes with very low emittance and to accommodate very long undulators, producing synchrotron radiation at x-ray wavelengths with extremely high brightness and coherent power. Two beamlines, each illuminated by a 2-m long, 77-mm period undulator magnet, are now operational and others are planned. In parasitic operation during colliding-beam runs at 14.5 GeV, these beamlines provide photons above 10 keV with a peak brightness of about 1016 photons/(s mm2 mrad2 ) within a 0.1% bandwidth. In low-emittance tests at 7.1 GeV, horizontal emittances of about 5 nm rad were measured, which is about the same as that planned for the new third-generation x-ray sources. With a current of 15 mA at 7.1 GeV, the present undulators deliver photon beams from 2.7 to 14 keV with a peak brightness of about 1017 . Higher performance levels are expected with the implementation of longer undulators and shorter period undulators. In the longer term, because of its large circumference and long straight sections, PEP could be further developed to achieve even higher performance levels with an emittance below 1 nm rad, very long undulators and picosecond bunches, resulting in one to two orders of magnitude higher brightness and coherent power.

Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsai, Cheng

Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed tomore » accelerate the particle beam in a short section of linac, circulate the beam, and then either continue to accelerate for energy boost or decelerate it for energy recovery. The beam properties of a linac machine are set at best by the initial particle sources. For storage rings, the beam equilibria are instead determined by the overall machine design. The modern recirculating machines share with linacs the advantages to both accelerate and preserve the beam with high beam quality, as well as efficiently reuse the accelerating components. The beamline design in such a machine configuration can however be much more complicated than that of linacs. As modern accelerators push toward the high-brightness or high-intensity frontier by demanding particles in a highly charged bunch (about nano-Coulomb per bunch) to concentrate in an ever-decreasing beam phase space (transverse normalized emittance about 1 μm and relative energy spread of the order of 10^-5 in GeV beam energy), the interaction amongst particles via their self-generated electromagnetic fields can potentially lead to coherent instabilities of the beam and thus pose significant challenges to the machine design and operation. In the past decade and a half, microbunching instability (MBI) has been one of the most challenging issues for such high-brightness or high-intensity beam transport, as it would degrade lasing performance in the fourth-generation light sources, reduce cooling efficiency in electron cooling facilities, and compromise the luminosity of colliding beams in lepton or lepton-hadron colliders. The dissertation work will focus on the MBI in modern recirculating electron accelerators. It has been known that the collective interactions, the coherent synchrotron radiation (CSR) and the longitudinal space charge (LSC) forces, can drive MBI. The CSR effect is a collective phenomenon in which the electrons in a curved motion, e.g. a bending dipole, emit radiation at a scale comparable to the micro-bunched structure of the bunch distribution. The LSC effect stems from non-uniformity of the charge distribution, acts as plasma oscillation, and can eventually accumulate an amount of energy modulation when the beam traverses a long section of a beamline. MBI can be seeded by non-uniformity or shot noise of the beam, which originates from granularity of the elementary charge. Through the aforementioned collective effects, the modulation of the bunch sub-structure can be amplified and, once the beam-wave interaction formed a positive feedback, can result in MBI. The problem of MBI has been intensively studied for linac-based facilities and for storage-ring accelerators. However, systematic studies for recirculation machines are still very limited and form a knowledge gap. Because of the much more complicated machine configuration of the recirculating accelerators than that of linacs, the existing MBI analysis needs to be extended to accommodate the high-brightness particle beam transport in modern recirculating accelerators. This dissertation is focused on theoretical investigation of MBI in such machine configuration in the following seven themes: (1) Development and generalization of MBI theory The theoretical formulation has been extended so as to be applicable to a general linear beamline lattice including horizontal and vertical transport bending elements, and beam acceleration or deceleration. These featured generalizations are required for MBI analysis in recirculation accelerators. (2) Construction of CSR impedance models In addition to the steady-state CSR interaction, it has been found that the exit transient effect (or CSR drift) can even result in more serious MBI in high-brightness recirculation arcs. The onedimensional free-space CSR impedances, especially the exit transients, are derived. The steady-state CSR impedance is also extended to non-ultrarelativistic beam energy for MBI analysis of low-energy merger sections in recirculating accelerators. (3) Numerical implementation of the derived semi-analytical formulation This includes the development of a semi-analytical Vlasov solver for MBI analysis, and also benchmarking of the solver against massive particle tracking simulations. (4) Exploration of multistage amplification behavior of CSR microbunching development The CSR-induced MBI acts as an amplifier, which amplifies the sub-bunch modulation of a beam. The amplification is commonly quantified by the amplification gain. A beam transport system can be considered as a cascaded amplifier. Unlike the two-stage amplification of four-dipole bunch compressor chicanes employed in linacs, the recirculation arcs, which are usually constituted by several tens of bending magnets, show a distinguishing feature of up to six-stage microbunching amplification for our example arc lattices. That is, the maximal CSR amplification gain can be proportional to the peak bunch current up to sixth power. A method to compare lattice performance has been developed in terms of gain coefficients, which nearly depend on the lattice properties only. This method has also proven to be an effective way to quantify the current dependence of the maximal (5) Control of CSR MBI in multibend transport or recirculation arcs The existing mitigation schemes of MBI mostly aim to linac-based accelerators and may not be practical to the recirculating accelerator facilities. Thus a set of conditions for suppression of CSR MBI was proposed and examined for example lattices from low (~100 MeV) to high (~1 GeV) energies. (6) Study of more aspects of microbunched structures in beam phase spaces For a cascaded amplifier in circuit electronics, the total amplification gain can be estimated as the product of individual gains. In a beam transport line of an accelerator, the (scalar) gain multiplication was examined and found to under-estimate the overall microbunching amplification. The concept of gain matrix was developed, which includes the density, energy and transverse-longitudinal modulations in a beam phase space, and used to analyze MBI for a proposed recirculating machine. Throughout the gain matrix approach, it reasonably gives the upper limit of spectral MBI gain curves. This extended analysis can be employed to study multi-pass recirculation. (7) Study of MBI for magnetized beams Driven by a recent energy-recovery-linac based cooler design for electron cooling at Jefferson Lab Electron-Ion Collider Project, the generalized theoretical formulation for MBI to a transversely coupled beam has been developed and applied to this study. A magnetized beam in general features non-zero canonical angular momentum, thus considered to be a transversely coupled beam. A novel idea of utilizing magnetized beam transport was proposed for improvement of cooling efficiency and possible mitigation of collective effects. A concern of MBI regarding this design was studied and excluded. The large transverse beam size associated with the beam magnetization is found to help suppress MBI via the transverse-longitudinal correlation.« less

Astrochemistry in TSR and CSR Ion Storage Rings

NASA Astrophysics Data System (ADS)

Novotny, Oldrich

2017-04-01

Dissociative recombination (DR) of molecular ions plays a key role in controlling the charge density and composition of the cold interstellar medium (ISM). Experimental data on DR are required in order to understand the chemical network in the ISM and related processes such as star formation from molecular clouds. Needed data include not only total reaction cross sections, but also the chemical composition and excitation states of the neutral products. Utilizing the TSR storage ring in Heidelberg, Germany, we have carried out DR measurements for astrophysically important molecular ions. We use a merged electron-ion beams technique combined with event-by-event fragment counting and fragment imaging. The count rate of detected neutral DR products yields the absolute DR rate coefficient. Imaging the distribution of fragment distances provides information on the kinetic energy released including the states of both the initial molecule and the final products. Additional kinetic energy sensitivity of the employed detector allows for identification of fragmentation channels by fragment-mass combination within each dissociation event. Such combined information is essential for studies on DR of polyatomic ions with multi-channel breakup. The recently commissioned Cryogenic Storage Ring (CSR) in Heidelberg, Germany, extends the experimental capabilities of TSR by operation at cryogenic temperatures down to 6 K. At these conditions residual gas densities down to 100 cm-3 can be reached resulting in beam storage times of several hours. Long storage in the cold environment allows the ions to relax down to their rotational ground state, thus mimicking well the conditions in the cold ISM. A variety of astrophysically relevant reactions will be investigated at these conditions, such as DR, electron impact excitation, ion-neutral collisions, etc. We report our TSR results on DR of HCl+ and D2Cl+. We also present first results from the CSR commissioning experiments.

Electric fields, electron production, and electron motion at the stripper foil in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Plum, M.

The beam instability at the Los Alamos Proton Storage Ring (PSR) most likely involves coupled oscillations between electrons and protons. For this instability to occur, there must be a strong source of electrons. Investigation of the various sources of electrons in the PSR had begun. Copious electron production is expected in the injection section because this section contains the stripper foil. This foil is mounted near the center of the beam pipe, and both circulating and injected protons pass through it, thus allowing ample opportunity for electron production. This paper discusses various mechanisms for electron production, beam-induced electric fields, and electron motion in the vicinity of the foil.

Lifetimes of relativistic heavy-ion beams in the High Energy Storage Ring of FAIR

NASA Astrophysics Data System (ADS)

Shevelko, V. P.; Litvinov, Yu. A.; Stöhlker, Th.; Tolstikhina, I. Yu.

2018-04-01

The High Energy Storage Ring, HESR, will be constructed at the Facility for Antiproton and Ion Research, FAIR, Darmstadt. For the first time, it will be possible to perform experiments with cooled high-intensity stable and radioactive heavy ions at highly relativistic energies. To design experiments at the HESR, realistic estimations of beam lifetimes are indispensable. Here we report calculated cross sections and lifetimes for typical U88+ , U90+ , U92+ , Sn49+ and Sn50+ ions in the energy range E = 400 MeV/u-5 GeV/u, relevant for the HESR. Interactions with the residual gas and with internal gas-jet targets are also considered.

Benchmarking of Touschek Beam Lifetime Calculations for the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, A.; Yang, B.

2017-06-25

Particle loss from Touschek scattering is one of the most significant issues faced by present and future synchrotron light source storage rings. For example, the predicted, Touschek-dominated beam lifetime for the Advanced Photon Source (APS) Upgrade lattice in 48-bunch, 200-mA timing mode is only ~ 2 h. In order to understand the reliability of the predicted lifetime, a series of measurements with various beam parameters was performed on the present APS storage ring. This paper first describes the entire process of beam lifetime measurement, then compares measured lifetime with the calculated one by applying the measured beam parameters. The resultsmore » show very good agreement.« less

Emittance measurements in low energy ion storage rings

NASA Astrophysics Data System (ADS)

Hunt, J. R.; Carli, C.; Resta-López, J.; Welsch, C. P.

2018-07-01

The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurement faces several challenges: non-zero dispersion, non-Gaussian beam distributions due to effects of the electron cooler and various systematic errors such as closed orbit offsets and inaccurate rms momentum spread estimation. In addition, diffusion processes, such as intra-beam scattering might lead to emittance overestimates. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA.

Development and operating experience of a 1.1-m-long superconducting undulator at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Ivanyushenkov, Y.; Harkay, K.; Borland, M.; Dejus, R.; Dooling, J.; Doose, C.; Emery, L.; Fuerst, J.; Gagliano, J.; Hasse, Q.; Kasa, M.; Kenesei, P.; Sajaev, V.; Schroeder, K.; Sereno, N.; Shastri, S.; Shiroyanagi, Y.; Skiadopoulos, D.; Smith, M.; Sun, X.; Trakhtenberg, E.; Xiao, A.; Zholents, A.; Gluskin, E.

2017-10-01

Development of superconducting undulators continues at the Advanced Photon Source (APS). Two years after successful installation and commissioning of the first relatively short superconducting undulator "SCU0" in Sector 6 of the APS storage ring, the second 1.1-m-long superconducting undulator "SCU1" was installed in Sector 1 of the APS. The device has been in user operation since its commissioning in May 2015. This paper describes the magnetic and cryogenic design of the SCU1 together with the results of stand-alone cold tests. The SCU1's magnetic and cryogenic performance as well as its operating experience in the APS storage ring are also presented.

The Effect of Gas Ion Bombardment on the Secondary Electron Yield of TiN, TiCN and TiZrV Coatings For Suppressing Collective Electron Effects in Storage Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Pimpec, F.; /PSI, Villigen; Kirby, R.E.

In many accelerator storage rings running positively charged beams, ionization of residual gas and secondary electron emission (SEE) in the beam pipe will give rise to an electron cloud which can cause beam blow-up or loss of the circulating beam. A preventative measure that suppresses electron cloud formation is to ensure that the vacuum wall has a low secondary emission yield (SEY). The SEY of thin films of TiN, sputter deposited Non-Evaporable Getters and a novel TiCN alloy were measured under a variety of conditions, including the effect of re-contamination from residual gas.

Search for the 1P 1 charmonium state in overlinepp annihilations at the CERN intersecting storage rings

NASA Astrophysics Data System (ADS)

Baglin, C.; Baird, S.; Bassompierre, G.; Borreani, G.; Brient, J.-C.; Broll, C.; Brom, J.-M.; Bugge, L.; Buran, T.; Burq, J.-P.; Bussière, A.; Buzzo, A.; Cester, R.; Chemarin, M.; Chevallier, M.; Escoubes, B.; Fay, J.; Ferroni, S.; Gracco, V.; Guillaud, J.-P.; Khan-Aronsen, E.; Kirsebom, K.; Kylling, A.; Ille, B.; Lambert, M.; Leistam, L.; Lundby, A.; Macri, M.; Marchetto, F.; Menichetti, E.; Mörch, Ch.; Mouellic, B.; Olsen, D.; Pastrone, N.; Petrillo, L.; Pia, M. G.; Poole, J.; Poulet, M.; Rinaudo, G.; Santroni, A.; Severi, M.; Skjevling, G.; Stapnes, S.; Stugu, B.; R704 Collaboration

1986-04-01

This experiment has been performed at the CERN Intersecting Storage Rings to study the direct formation of charmonium states in antiproton-proton annihilations. The experimental program has partly been devoted to an inclusive scan for overlinepp → J/ψ + X in the range 3520-3530 MeV/ c2. A cluster of five events has been observed in a narrow energy band, centred on the centre of gravity of the 3P J states where the 1P 1 is expected to be. When interpreted as a new resonace, these data yield a mass m = 3525.4±0.8 MeV/ c2.

On Organic Material in E Ring Ice Grains

NASA Astrophysics Data System (ADS)

Postberg, F.; Khawaja, N.; Reviol, R.; Nölle, L.; Klenner, F.; Hsu, H. W.; Horanyi, M.

2015-12-01

Pure water ice dominates the composition of the micron and sub-micron sized dust particles in Saturn's E-ring, a ring constantly replenished by active ice jets of the moon Enceladus [1]. Details about the composition of this tenuous, optically thin ring can only be constrained by in situ measurements. The Cosmic Dust Analyzer (CDA) onboard Cassini investigates the composition of these grains by cationic time-of-flight mass spectra of individual ice grains hitting the instruments target surface. From these spectra three compositional types of E ring ice grains have been identified previously [2,3]: Type-1: Almost pure water, Type-2: Enriched in organics, and Type-3: Enriched in salt. Unlike Type-1 and 3, organic-enriched Type-2 spectra have not yet been investigated in depth. Here we report the first detailed compositional analysis of this type. The spectra analysis is supported by a large-scale laboratory ground campaign yielding a library of analogue spectra for organic material embedded in a water ice matrix. In contrast to Type 1 and 3, Type-2 spectra display a great compositional diversity, which indicates varying contributions of several organic species. So far we have identified characteristic fragment patterns of at least three classes of organic compounds: aromatic species, amines, and carbonyl group species. Work is in progress to quantify concentrations of the identified species and to assign yet un-specified organic mass lines in Type 2 spectra. Due to the dynamical evolution of the orbital elements of E ring grains a large fraction collides with the icy moons embedded in the E ring. Therefore, the organic components identified by CDA can accumulate on the surfaces of these bodies over time. Ref: :[1]Kempf et al., Icarus-206, 2010. [2]Postberg et al., Nature-459, 2009. [3]Postberg et al., Icarus-193, 2008.

Ring-slope interactions and the formation of the western boundary current in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Vidal, VíCtor M. V.; Vidal, Francisco V.; Meza, Eustorgio; Portilla, Josué; Zambrano, Lorenzo; Jaimes, BenjamíN.

1999-09-01

Hydrographic data from the Gulf of Mexico (gulf) provide evidence that a western boundary current was set up by the interaction of an anticyclonic Loop Current (LC) ring with the continental margin of the western gulf during March-August 1985. The March 1985 geostrophic circulation reveals a remnant anticyclonic ring colliding with the slope. During this collision, two cyclonic rings were shed as the anticyclone transferred vorticity to the surrounding slope water. During July-August 1985, the ring triad weakened and evolved into a ˜900-km-long, north flowing, along-slope, western boundary current and cyclonic-anticyclonic ring pairs distributed throughout the central and western gulf. This western boundary current attained maximum northward flow speeds of 25 cm s-1 and an 8.3-Sv mass transport between 94°-96°W at 25°N. Our March-August 1985 observations reveal that the residence time and decay period of LC anticyclones in the western gulf may exceed 150 days. Within this time period the western gulf's cyclonic-anticyclonic vorticity field decayed ˜50%. Thus the western boundary current's evolutionary period, from its gestation to its absolute decay, is estimated to be of the order of 300 days. Although the presence of a western boundary current in the gulf has been attributed to the annual wind stress curl cycle [Sturges, 1993], our analyses of the western gulf March and July-August 1985 ring-driven geostrophic circulation and corresponding (January, February and May, June 1985) monthly mean synoptic wind stress curl distributions reveal that these constitute competing forcing mechanisms for the gulf's regional circulation. However, when very strong local forcing such as large eddies are present, the wind-driven background circulation is overwhelmed by such eddy forcing.

Modification of a liquid hydrogen tank for integrated refrigeration and storage

NASA Astrophysics Data System (ADS)

Swanger, A. M.; Jumper, K. M.; Fesmire, J. E.; Notardonato, W. U.

2015-12-01

The modification and outfitting of a 125,000-liter liquid hydrogen tank was performed to provide integrated refrigeration and storage capability. These functions include zero boil-off, liquefaction, and densification and therefore require provisions for sub-atmospheric tank pressures within the vacuum-jacketed, multilayer insulated tank. The primary structural modification was to add stiffening rings inside the inner vessel. The internal stiffening rings were designed, built, and installed per the ASME Boiler and Pressure Vessel Code, Section VIII, to prevent collapse in the case of vacuum jacket failure in combination with sub-atmospheric pressure within the tank. For the integrated refrigeration loop, a modular, skeleton-type heat exchanger, with refrigerant temperature instrumentation, was constructed using the stiffening rings as supports. To support the system thermal performance testing, three custom temperature rakes were designed and installed along the 21-meter length of the tank, once again using rings as supports. The temperature rakes included a total of 20 silicon diode temperature sensors mounted both vertically and radially to map the bulk liquid temperature within the tank. The tank modifications were successful and the system is now operational for the research and development of integrated refrigeration technology.

Measurement of pion, kaon and proton production in proton–proton collisions at $$\\sqrt{s} = 7$$ TeV

DOE PAGES

Adam, J.; Adamová, D.; Aggarwal, M. M.; ...

2015-05-27

The measurement of primary π ±, K ±, p and p¯ production at mid-rapidity (|y|< 0.5) in proton–proton collisions at √s = 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/c for pions, from 0.2 up to 6 GeV/c for kaons and from 0.3 up to 6 GeV/c for protons. The measured spectra and particlemore » ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Lastly, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.« less

Tidal torques on infrequently colliding particle disks in binary systems and the truncation of the asteroid belt

NASA Technical Reports Server (NTRS)

Franklin, F. A.; Lecar, M.; Lin, D. N. C.; Papaloizou, J.

1980-01-01

Conditions leading to the truncation, at the 2:1 resonance, of a disk of infrequently colliding particles surrounding the primary of a binary system are studied numerically and analytically. Attention is given to the case in which the mass ratio, q, is sufficiently small (less than about 0.1) and the radius of the disk centered on the primary allowably larger, so that first-order orbit-orbit resonances between ring material and the secondary can lie within it. Collisions are found to be less frequent than q to the -2/3 power orbital periods (the period of the forced eccentricity at the 2:1 resonance), and truncation occurs and Kirkwood gaps are produced only if the particle eccentricity is less than some critical value, estimated to be of order q to the 5/9 power, or approximately 0.02 for the sun-Jupiter case having q equal to 10 to the -3rd power.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkel, L.; Dejus, R.; Maines, J.

This report is a description of the current status of the magnetic measurement facility and is a basic instructional manual for the operation of the facility and its components. Please refer to the appendices for more detailed information about specific components and procedures. The purpose of the magnetic measurement facility is to take accurate measurements of the magnetic field in the gay of the IDs in order to determine the effect of the ID on the stored particle beam and the emitted radiation. The facility will also play an important role when evaluating new ideas, novel devices, and inhouse prototypesmore » as part of the ongoing research and development program at the APS. The measurements will be performed with both moving search coils and moving Hall probes. The IDs will be evaluated by computer modeling of the emitted radiation for any given (measured) magnetic field map. The quality of the magnetic field will be described in terms of integrated multipoles for the effect on Storage Ring performance and in terms of the derived trajectories for the emitted radiation. Before being installed on the Storage Ring, every device will be measured and characterized to assure that it is compatible with Storage Ring requirements and radiation specifications. The accuracy that the APS needs to achieve for magnetic measurements will be based on these specifications.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huamg, C. W., E-mail: huang.zw@nsrrc.org.tw; Hwang, C. S., E-mail: cshwang@nsrrc.org.tw; Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan

The Taiwan Photon Source (TPS) has been successfully commissioned. However, the minimum emittance in the TPS lattice is 1.6 nm rad. In the existing TPS storage ring lattice, it is imperative to reduce the emittance to below 1 nm rad. Therefore, a feasibility study for reducing the effective emittance of the TPS storage ring by using a Robinson wiggler was launched; the reduction is necessary to enhance the photon brilliance. In this study, a permanent-magnet multiperiod Robinson wiggler (MRW) was developed for use instead of the single-period Robinson wiggler. In general, the quadruple field of a combined function magnet inmore » the storage ring is approximately few tesla per meter. According to beam dynamic analysis, we found that it is necessary to adopt a high gradient (40 T/m) combined-function MRW magnet to reduce the emittance effectively. Therefore, a high gradient field strength is required in the combined function MRW magnet. In this study, the quadrupole field strength of the MRW magnet was allowed to be approximately 40 T/m at a magnet gap of 20 mm. The period length of the MRW magnet was 300 mm and the period number was 16. The of MRWs is discussed in regard to the possibility of increasing the photon brilliance from IU22.« less

Electron cooling of a bunched ion beam in a storage ring

NASA Astrophysics Data System (ADS)

Zhao, He; Mao, Lijun; Yang, Jiancheng; Xia, Jiawen; Yang, Xiaodong; Li, Jie; Tang, Meitang; Shen, Guodong; Ma, Xiaoming; Wu, Bo; Wang, Geng; Ruan, Shuang; Wang, Kedong; Dong, Ziqiang

2018-02-01

A combination of electron cooling and rf system is an effective method to compress the beam bunch length in storage rings. A simulation code based on multiparticle tracking was developed to calculate the bunched ion beam cooling process, in which the electron cooling, intrabeam scattering (IBS), ion beam space-charge field, transverse and synchrotron motion are considered. Meanwhile, bunched ion beam cooling experiments have been carried out in the main cooling storage ring (CSRm) of the Heavy Ion Research Facility in Lanzhou, to investigate the minimum bunch length obtained by the cooling method, and study the dependence of the minimum bunch length on beam and machine parameters. The experiments show comparable results to those from simulation. Based on these simulations and experiments, we established an analytical model to describe the limitation of the bunch length of the cooled ion beam. It is observed that the IBS effect is dominant for low intensity beams, and the space-charge effect is much more important for high intensity beams. Moreover, the particles will not be bunched for much higher intensity beam. The experimental results in CSRm show a good agreement with the analytical model in the IBS dominated regime. The simulation work offers us comparable results to those from the analytical model both in IBS dominated and space-charge dominated regimes.

Mass Transfer via Low-Velocity Rebound in a Microgravity Environment

NASA Astrophysics Data System (ADS)

Jarmak, S. G.; Colwell, J. E.; Brisset, J.; Dove, A.; Brown, A. Q.

2017-12-01

Observations of low-velocity collisions (< 1 m/s) between μm to cm-size particles in a microgravity environment are crucial to an understanding of the surface properties of small, airless bodies as well as the processes that lead to their formation. The COLLIDE (Collisions Into Dust Experiment) and PRIME (Physics of Regolith Impacts in Microgravity Experiment) programs created impacts into simulated planetary regolith with cm-scale impactors to observe ejecta production and coefficients of restitution in microgravity. These experiments were carried out on orbit (COLLIDE, COLLIDE-2), in suborbital space (COLLIDE-3), and on parabolic airplane flights (PRIME) under vacuum. Some impacts at speeds less than 40 cm/s resulted in mass transfer from the target regolith onto the impactor. To study these mass-transfer collisions in more detail without the cost or time requirements of spaceflight or parabolic flights, we developed an experimental apparatus in a laboratory drop tower (free-fall time 0.75 s) and performed experiments at standard pressure. The impactor is suspended from a spring and remains in contact with the bed of regolith until free-fall allows the spring to retract and pull the impactor upwards. This method allowed us to simulate the rebound portion of a low-velocity collision in a laboratory microgravity environment. We achieved rebound velocities of 10 - 60 cm/s, and we observed mass transfer events with rebound speeds below 40 cm/s. The amount of mass transfer produced was more significant than a monolayer of granular material, but less than the amount observed in the COLLIDE and PRIME experiments. These mass-transfer collisions may play a role in the growth of planetesimals. We will present the results of our laboratory-based studies where we vary impact velocity and target material, and discuss implications for collisional evolution in the protoplanetary disk and planetary rings.

Semiconductor laser-based optoelectronics oscillators

NASA Astrophysics Data System (ADS)

Yao, X. S.; Maleki, Lute; Wu, Chi; Davis, Lawrence J.; Forouhar, Siamak

1998-08-01

We demonstrate the realization of coupled opto-electronic oscillators (COEO) with different semiconductor lasers, including a ring laser, a Fabry-Perot laser, and a colliding pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices, we obtained optical pulses as short as 6 picoseconds and RF signals as high in frequency as 18 GHz with a spectral purity comparable with a HP8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals.

InP femtosecond mode-locked laser in a compound feedback cavity with a switchable repetition rate

NASA Astrophysics Data System (ADS)

Lo, Mu-Chieh; Guzmán, Robinson; Carpintero, Guillermo

2018-02-01

A monolithically integrated mode-locked semiconductor laser is proposed. The compound ring cavity is composed of a colliding pulse mode-locking (ML) subcavity and a passive Fabry-Perot feedback subcavity. These two 1.6 mm long subcavities are coupled by using on-chip reflectors at both ends, enabling harmonic mode locking. By changing DC-bias conditions, optical mode spacing from 50 to 450 GHz is experimentally demonstrated. Ultrafast pulses shorter than 0.3 ps emitted from this laser diode are shown in autocorrelation traces.

Injector for the University of Maryland Electron Ring (UMER)

NASA Astrophysics Data System (ADS)

Kehne, D.; Godlove, T.; Haldemann, P.; Bernal, S.; Guharay, S.; Kishek, R.; Li, Y.; O'Shea, P.; Reiser, M.; Yun, V.; Zou, Y.; Haber, I.

2001-05-01

The electron beam injector constructed by FM technologies for the University of Maryland Electron Ring (UMER) program is described. The program will use an electron beam to model space-charge-dominated ion beams in a recirculating linac for heavy ion inertial fusion, as well as for high-current muon colliders. The injector consists of a 10 keV, 100 mA electron gun with 50-100 nsec pulse width and a repetition rate of 120 Hz. The e-gun system includes a 6-mask, rotatable aperture plate, a Rogowski current monitor, an ion pump, and a gate valve. The injector beamline consists of a solenoid, a five-quadrupole matching section, two diagnostic chambers, and a fast current monitor. An independent diagnostic chamber also built for UMER will be used to measure horizontal and vertical emittance, current, energy, energy spread, and the evolution of the beam envelope and profile along the injector beamline.

BEAM DYNAMICS ANALYSIS FOR THE ULTRA-FAST KICKER IN CIRCULAR COOLER RING OF JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Yulu; Wang, Haipeng; Rimmer, Robert A.

An ultra-fast kicker system consisting of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency. Thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is being developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mAmore » - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesize such a kicker waveform and the comparison made by the beam dynamics tracking in Elegant will be discussed.« less

Kicker field simulation and measurement for the muon g-2 experiment at FNAL

NASA Astrophysics Data System (ADS)

Chang, Seung Pyo; Kim, Young Im; Choi, Jihoon; Semertzidis, Yannis; muon g-2 experiment Collaboration

2017-01-01

In the Muon g-2 experiment, muon beam is injected to the storage ring in a slightly tilted orbit whose center is 77 mm away from the center of the ring. The kicker is needed to send the muon beam to the central orbit. The magnetic kicker is designed for the experiment and about 0.1 Tm field integral is needed. The peak current pulse is 4200 A to make this field integral. This strong kicker pulse could make unwanted eddy current occur. This eddy current could spoil the main magnetic field of the storage ring. This could be a critical threat to the precision of experiment. The kicker field simulation has done using OPERA to estimate the effects. Also the kicker field should be measured based on Faraday effect. The measurement has tested in the lab before install the experiment area. In this presentation, the simulation and measurement results will be discussed. This work was supported by IBS-R017-D1-2016-a00.

Nuclear-matter radius studies from 58Ni(α ,α ) experiments at the GSI Experimental Storage Ring with the EXL facility

NASA Astrophysics Data System (ADS)

Zamora, J. C.; Aumann, T.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, Th.; Kuilman, M.; Litvinov, S.; Litvinov, Yu. A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; von Schmid, M.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zenihiro, J.

2017-09-01

A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of 58Ni. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored 58Ni beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered α -recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of 58Ni with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Talman, Richard M.; Talman, John D.

Proposed methods for measuring the electric dipole moment (EDM) of the proton use an intense, polarized proton beam stored in an all-electric storage ring “trap.” At the “magic” kinetic energy of 232.792 MeV, proton spins are “frozen,” for example always parallel to the instantaneous particle momentum. Energy deviation from the magic value causes in-plane precession of the spin relative to the momentum. Any nonzero EDM value will cause out-of-plane precession—measuring this precession is the basis for the EDM determination. A proposed implementation of this measurement shows that a proton EDM value of 10 –29e–cm or greater will produce a statisticallymore » significant, measurable precession after multiply repeated runs, assuming small beam depolarization during 1000 s runs, with high enough precision to test models of the early universe developed to account for the present day particle/antiparticle population imbalance. This paper describes an accelerator simulation code, eteapot, a new component of the Unified Accelerator Libraries (ual), to be used for long term tracking of particle orbits and spins in electric bend accelerators, in order to simulate EDM storage ring experiments. Though qualitatively much like magnetic rings, the nonconstant particle velocity in electric rings gives them significantly different properties, especially in weak focusing rings. Like the earlier code teapot (for magnetic ring simulation) this code performs exact tracking in an idealized (approximate) lattice rather than the more conventional approach, which is approximate tracking in a more nearly exact lattice. The Bargmann-Michel-Telegdi (BMT) equation describing the evolution of spin vectors through idealized bend elements is also solved exactly—original to this paper. Furthermore the idealization permits the code to be exactly symplectic (with no artificial “symplectification”). Any residual spurious damping or antidamping is sufficiently small to permit reliable tracking for the long times, such as the 1000 s assumed in estimating the achievable EDM precision. This paper documents in detail the theoretical formulation implemented in eteapot. An accompanying paper describes the practical application of the eteapot code in the Universal Accelerator Libraries (ual) environment to “resurrect,” or reverse engineer, the “AGS-analog” all-electric ring built at Brookhaven National Laboratory in 1954. Of the (very few) all-electric rings ever commissioned, the AGS-analog ring is the only relativistic one and is the closest to what is needed for measuring proton (or, even more so, electron) EDM’s. As a result, the companion paper also describes preliminary lattice studies for the planned proton EDM storage rings as well as testing the code for long time orbit and spin tracking.« less

An undulator based soft x-ray source for microscopy on the Duke electron storage ring

NASA Astrophysics Data System (ADS)

Johnson, Lewis Elgin

1998-09-01

This dissertation describes the design, development, and installation of an undulator-based soft x-ray source on the Duke Free Electron Laser laboratory electron storage ring. Insertion device and soft x-ray beamline physics and technology are all discussed in detail. The Duke/NIST undulator is a 3.64-m long hybrid design constructed by the Brobeck Division of Maxwell Laboratories. Originally built for an FEL project at the National Institute of Standards and Technology, the undulator was acquired by Duke in 1992 for use as a soft x-ray source for the FEL laboratory. Initial Hall probe measurements on the magnetic field distribution of the undulator revealed field errors of more than 0.80%. Initial phase errors for the device were more than 11 degrees. Through a series of in situ and off-line measurements and modifications we have re-tuned the magnet field structure of the device to produce strong spectral characteristics through the 5th harmonic. A low operating K has served to reduce the effects of magnetic field errors on the harmonic spectral content. Although rms field errors remained at 0.75%, we succeeded in reducing phase errors to less than 5 degrees. Using trajectory simulations from magnetic field data, we have computed the spectral output given the interaction of the Duke storage ring electron beam and the NIST undulator. Driven by a series of concerns and constraints over maximum utility, personnel safety and funding, we have also constructed a unique front end beamline for the undulator. The front end has been designed for maximum throughput of the 1st harmonic around 40A in its standard mode of operation. The front end has an alternative mode of operation which transmits the 3rd and 5th harmonics. This compact system also allows for the extraction of some of the bend magnet produced synchrotron and transition radiation from the storage ring. As with any well designed front end system, it also provides excellent protection to personnel and to the storage ring. A diagnostic beamline consisting of a transmission grating spectrometer and scanning wire beam profile monitor was constructed to measure the spatial and spectral characteristics of the undulator radiation. Test of the system with a circulating electron beam has confirmed the magnetic and focusing properties of the undulator, and verified that it can be used without perturbing the orbit of the beam.

The temporal distribution and carbon storage of large oak wood in streams and floodplain deposits

Treesearch

Richard P. Guyette; Daniel C. Dey; Michael C. Stambaugh

2008-01-01

We used tree-ring dating and 14C dating to document the temporal distribution and carbon storage of oak (Quercus spp.) wood in trees recruited and buried by streams and floodplains in northern Missouri, USA. Frequency distributions indicated that oak wood has been accumulating in Midwest streams continually since at least the...

A FODO racetrack ring for nuSTORM: design and optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, A.; Bross, A.; Neuffer, D.

2017-07-01

The goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ~ 480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize the arcmore » length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.« less

Sensory acceptability of squid rings gamma irradiated for shelf-life extension

NASA Astrophysics Data System (ADS)

Tomac, Alejandra; Cova, María C.; Narvaiz, Patricia; Yeannes, María I.

2017-01-01

The feasibility of extending the shelf-life of a squid product by gamma irradiation was analyzed. Illex argentinus rings were irradiated at 4 and 8 kGy; and stored at 4±1 °C during 77 days. No mesophilic bacteria, enterobacteriaceae and coliforms were detected in irradiated rings during storage. Psychrotrophic bacteria were significantly reduced by irradiation; their counts were fitted to a growth model which was further used for shelf-life estimations: 3 and 27 days for 0 and 4 kGy, respectively. Initially, non-irradiated as well as irradiated rings had very good sensory scores. The overall acceptability of 4 and 8 kGy rings did not decrease during 27 and 64 days, respectively, while control samples spoiled after 3 days. A radiation dose range for squid rings preservation was defined, which attained the technological shelf-life extension objective, without impairing sensory quality.

Simulation of emittance dilution in electron storage ring from Compton backscattering

NASA Astrophysics Data System (ADS)

Blumberg, L. N.; Blum, E.

A Monte-Carlo simulation of Compton backscattered kappa(sub L) = 3.2-micron photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of delta(sub E) = 11.9-keV for a sample of 10(exp 7) single scattering events. Electrons are sampled from a beam of natural energy spread sigma(sub E) = 5.6-keV and damped transverse angle spreads sigma(sub x)(prime) = .041-mrad and sigma(sub y)(prime) = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered x-rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performed in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads sigma(sub xo) = .102-mm, sigma(sub x(prime)o) = .041-mrad, sigma(sub yo) = .018-mm, sigma(sub y(prime)o) = .052-mrad, sigma(sub (phi)o) = 22-mrad and sigma(sub Eo) = 6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of f(sub RF) = 211.54-MHz and peak voltage V(sub m)=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of delta(sub E) = 124-keV. The transverse widths are only slightly increased from their original values, i.e. delta(sub x) = .106-mm and delta(sub x)(prime) = .043 mrad. The scaled energy spread of delta(sub E) approximately = 360-keV for approximately 350,000 turns desired in a 10-msec x-ray angiography exposure is well within the RF bucket used here; even V(sub m) less than 50-kV is adequate. Further, the electron energy spread adds a negligible RMS x-ray energy spread of delta(sub Ex) = .32-keV. The electron energy damping time of tau(sub E) = 379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off of the ring between heart cycles.

Patterns of Storage, Synthesis and Changing Light Levels Revealed by Carbon Isotope Microsampling within Eocene Metasequoia Tree Rings

NASA Astrophysics Data System (ADS)

Jahren, H.; Sternberg, L.

2005-12-01

Fossil tree rings from Axel Heiberg Island were microanalyzed for δ13C value in order to assess patterns of tree growth and carbon storage within the Middle Eocene (~45 Ma) Arctic paleoenvironment. Wood from four Metasequoia-type individuals was subsampled for analysis: each individual fossil consisted of between 4 and 10 large (~1 cm thick) consecutive tree rings. One of the fossils displayed an obvious concentric pattern, allowing for the determination of the direction of growth with isotopic pattern. Each ring was divided into ~1 mm thick subsamples, resulting in 5-10 δ13C value determinations per period of ring growth (i.e., growing season). All rings revealed a distinct pattern that was characteristic across growing seasons and across individual fossils. Early in the season, δ13C was at its highest value but descended systematically and sharply to its lowest value at the end of the growing season. Total decrease ranged between 3 and 5 ‰ over the course of each growing season. Identical patterns were observed in the δ13C value of alpha-cellulose isolated from each subsample, indicating that the trends observed did not represent changing levels of secondary metabolites, but rather a seasonal adjustment in the bulk source of carbon used during biosynthesis. Our results are consistent with the following annual pattern of wood synthesis 1.) complete dependence on the mobilization of stored carbon compounds early in the growing season; 2.) systematically increasing use of actively-acquired photosynthate during the growing season; 3.) complete reliance on active photosynthate by the end of the growing season. An additional and significant source of 13C discrimination is declining light levels late in the growing season, and likely contributes to the extreme pattern of δ13C decrease seen across each ring. Our results mimic those seen from modern broadleaf deciduous trees (Helle & Schlesser 2004), but differ from those seen in modern conifers (Barbour et al 2002), underlining the important influence of dormancy, storage and changing light levels on carbon cycling within the Paleogene polar forests. Helle & Schleser 2004: Plant, Cell and Environment 27:367-380. Barbour, Walcroft & Farquhar 2002: Plant, Cell and Environment 25: 1483-1499.

The design improvement of horizontal stripline kicker in TPS storage ring

NASA Astrophysics Data System (ADS)

Chou, P. J.; Chan, C. K.; Chang, C. C.; Hsu, K. T.; Hu, K. H.; Kuan, C. K.; Sheng, I. C.

2017-07-01

We plan to replace the existing horizontal stripline kicker of the transverse feedback system with an improved design. Large reflected power was observed at the downstream port of stripline kicker driven by the feedback amplifier. A rapid surge of vacuum pressure was observed when we tested the high current operation in TPS storage ring in April 2016. A burned feedthrough of the horizontal stripline kicker was discovered during a maintenance shutdown. The improved design is targeted to reduce the reflection of driving power from feedback system and to reduce beam induced RF heating. This major modification of the design is described. The results of RF simulation performed with the electromagnetic code GdfidL are reported as well.

Ultrashort high-brightness pulses from storage rings

NASA Astrophysics Data System (ADS)

Khan, Shaukat

2017-09-01

The brightness of short-wavelength radiation from accelerator-based sources can be increased by coherent emission in which the radiation intensity scales with the number of contributing electrons squared. This requires a microbunched longitudinal electron distribution, which is the case in free-electron lasers. The brightness of light sources based on electron storage rings was steadily improved, but could profit further from coherent emission. The modulation of the electron energy by a continuous-wave laser field may provide steady-state microbunching in the infrared regime. For shorter wavelengths, the energy modulation can be converted into a temporary density modulation by a dispersive chicane. One particular goal is coherent emission from a very short "slice" within an electron bunch in order to produce ultrashort radiation pulses with high brightness.

Astrochemistry at the Cryogenic Storage Ring

NASA Astrophysics Data System (ADS)

Kreckel, Holger; Becker, Arno; Blaum, Klaus; Breitenfeldt, Christian; George, Sebastian; Göck, Jürgen; Grieser, Manfred; Grussie, Florian; Guerin, Elisabeth; Heber, Oded; Karthein, Jonas; Krantz, Claude; Meyer, Christian; Mishra, Preeti; Novotny, Oldrich; O'Connor, Aodh; Saurabh, Sunny; Schippers, Stefan; Spruck, Kaija; Kumar, S. Sunil; Urbain, Xavier; Vogel, Stephen; von Hahn, Robert; Wilhelm, Patrick; Wolf, Andreas; Zajfman, Daniel

2017-01-01

Almost 200 different molecular species have been identified in space, and this number continues to grow steadily. This surprising molecular diversity bears witness to an active reaction network, in which molecular ions are the main drivers of chemistry in the gas phase. To study these reactions under controlled conditions in the laboratory is a major experimental challenge. The new Cryogenic Storage Ring (CSR) that has recently been commissioned at the Max Planck Institute for Nuclear Physics in Heidelberg will serve as an ideal testbed to study cold molecular ions in the gas phase. With residual gas densities of <140 cm-3 and temperatures below 10K, the CSR will allow for merged beams collision studies involving molecular ions, neutral atoms, free electrons and photons under true interstellar conditions.

Measurement of the Two-Photon Exchange Contribution to the Elastic e ± p Scattering Cross Sections at the VEPP-3 Storage Ring

DOE PAGES

Rachek, I. A.; Arrington, J.; Dmitriev, V. F.; ...

2015-02-12

The ratio of the elastic e +p to e –p scattering cross sections has been measured precisely, allowing the determination of the two-photon exchange contribution to these processes. This neglected contribution is believed to be the cause of the discrepancy between the Rosenbluth and polarization transfer methods of measuring the proton electromagnetic form factors. The experiment was performed at the VEPP-3 storage ring at beam energies of 1.6 and 1.0 GeV and at lepton scattering angles between 15° and 105°. The data obtained show evidence of a significant two-photon exchange effect. Furthermore, the results are compared with several theoretical predictions.

Measurement of Tensor Analyzing Powers for Elastic Electron Scattering from a Polarized {sup 2}H Target Internal to a Storage Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferro-Luzzi, M.; Bouwhuis, M.; Passchier, E.

1996-09-01

We report an absolute measurement of the tensor analyzing powers {ital T}{sub 20} and {ital T}{sub 22} in elastic electron-deuteron scattering at a momentum transfer of 1.6 fm{sup {minus}1}. The novel approach of this measurement is the use of a tensor polarized {sup 2}H target internal to an electron storage ring, with {ital in} {ital situ} measurement of the polarization of the target gas. Scattered electrons and recoil deuterons were detected in coincidence with two large acceptance nonmagnetic detectors. The techniques demonstrated have broad applicability to further measurements of spin-dependent electron scattering. {copyright} {ital 1996 The American Physical Society.}

ALS superbend magnet performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marks, Steve; Zbasnik, John; Byrne, Warren

2001-12-10

The Lawrence Berkeley National Laboratory has been engaged in the design, construction and testing of four superconducting dipoles (Superbends) that are installed in three arcs of the Advanced Light Source (ALS), with the fourth magnet as a spare. This represents a major upgrade to the ALS providing an enhanced flux and brightness at photon energies above 10 keV. In preparation for installation, an extensive set of tests and measurements have been conducted to characterize the magnetic and cryogenic performance of the Superbends and to fiducialize them for accurate placement in the ALS storage ring. The magnets are currently installed, andmore » the storage ring is undergoing final commissioning. This paper will present the results of magnetic and cryogenic testing.« less

Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stillwell, B.; Brajuskovic, B.; Carter, J.

A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Up-grade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation; insufficient beam position monitor stability; excessive beam impedance; excessive heating by induced electrical surface currents; and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mockup assemblies; performing mechanical testing of chamber weld joints; developing computational tools; investigating design alternatives; and performing electrical bench measurements. Status of these activities andmore » some of what has been learned to date will be shared.« less

Prospects of high-resolution resonant X-ray inelastic scattering studies on solid materials, liquids and gases at diffraction-limited storage rings.

PubMed

Schmitt, Thorsten; de Groot, Frank M F; Rubensson, Jan Erik

2014-09-01

The spectroscopic technique of resonant inelastic X-ray scattering (RIXS) will particularly profit from immensely improved brilliance of diffraction-limited storage rings (DLSRs). In RIXS one measures the intensities of excitations as a function of energy and momentum transfer. DLSRs will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size to new limits. With RIXS one nowadays probes a broad range of electronic systems reaching from simple molecules to complex materials displaying phenomena like peculiar magnetism, two-dimensional electron gases, superconductivity, photovoltaic energy conversion and heterogeneous catalysis. In this article the types of improved RIXS studies that will become possible with X-ray beams from DLSRs are envisioned.

FY2017 status report: Model 9975 O-ring fixture long-term leak performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daugherty, W. L.

A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially andmore » have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. Leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The 300 °F GLT O-ring fixtures failed after 2.8 to 5.7 years at temperature. The remaining GLT O-ring fixtures aging at 300 ºF were retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 9 to 10.5 years, or in GLT O-ring fixtures aging at 270 ºF for 5.7 years. These aging temperatures bound O-ring temperatures anticipated during normal storage in K-Area Complex (KAC). Leak test failures have been experienced in all of the GLT-S O-ring fixtures aging at 300 ºF and above. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 and 250 ºF for 6.9 to 7.5 years. Data from the O-ring fixtures are generally consistent with results from compression stress relaxation testing, and provide confidence in the predictive models based on those results. However, uncertainty still exists in extrapolating these elevated temperature results to the lower temperatures of interest for normal storage in KAC. Measurement of compression set in O-rings removed from failed fixtures, compared to that from KAC surveillance O-rings, indicates margin remains for O-rings still in service. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stancari, Giulio

Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complementmore » the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.« less

Upgrades at the Duke Free Electron Laser Laboratory

NASA Astrophysics Data System (ADS)

Howell, Calvin R.

2004-11-01

Major upgrades to the storage-ring based photon sources at the Duke Free Electron Laser Laboratory (DFELL) are underway. The photon sources at the DFELL are well suited for research in the areas of medicine, biophysics, accelerator physics, nuclear physics and material science. These upgrades, which will be completed by the summer 2006, will significantly enhance the capabilities of the ultraviolet (UV) free-electron laser (FEL) and the high intensity gamma-ray source (HIGS). The HIGS is a relatively new research facility at the DFELL that is operated jointly by the DFELL and the Triangle Universities Nuclear Laboratory. The gamma-ray beam is produced by Compton back scattering of the UV photons inside the FEL optical cavity off the circulating electrons in the storage ring. The gamma-ray beam is 100% polarized and its energy resolution is selected by collimation. The capabilities of the upgraded facility will be described, the status of the upgrades will be summarized, and the proposed first-generation research program at HIGS will be presented.

Next Generation Muon g-2 Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hertzog, David W.

2015-12-02

I report on the progress of two new muon anomalous magnetic moment experiments, which are in advanced design and construction phases. The goal of Fermilab E989 is to reduce the experimental uncertainty ofmore » $$a_\\mu$$ from Brookhaven E821 by a factor of 4; that is, $$\\delta a_\\mu \\sim 16 \\times 10^{-11}$$, a relative uncertainty of 140~ppb. The method follows the same magic-momentum storage ring concept used at BNL, and pioneered previously at CERN, but muon beam preparation, storage ring internal hardware, field measuring equipment, and detector and electronics systems are all new or upgraded significantly. In contrast, J-PARC E34 will employ a novel approach based on injection of an ultra-cold, low-energy, muon beam injected into a small, but highly uniform magnet. Only a small magnetic focusing field is needed to maintain storage, which distinguishes it from CERN, BNL and Fermilab. E34 aims to roughly match the previous BNL precision in their Phase~1 installation.« less

CCD-based vertex detector for ILC

NASA Astrophysics Data System (ADS)

Stefanov, Konstantin D.

2006-12-01

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide a superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last few years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips, to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. The first set of prototype devices have been successfully designed, manufactured and tested, with second generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype has been manufactured.

Dynamics of a class of vortex rings. Ph.D. Thesis - Stanford Univ.

NASA Technical Reports Server (NTRS)

Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.

1989-01-01

The contour dynamics method is extended to vortex rings with vorticity varying linearly from the symmetry axis. An elliptic core model is also developed to explain some of the basic physics. Passage and collisions of two identical rings are studied focusing on core deformation, sound generation and stirring of fluid elements. With respect to core deformation, not only the strain rate but how rapidly it varies is important and accounts for greater susceptibility to vortex tearing than in two dimensions. For slow strain, as a passage interaction is completed and the strain relaxes, the cores return to their original shape while permanent deformations remain for rapidly varying strain. For collisions, if the strain changes slowly the core shapes migrate through a known family of two-dimensional steady vortex pairs up to the limiting member of the family. Thereafter energy conservation does not allow the cores to maintain a constant shape. For rapidly varying strain, core deformation is severe and a head-tail structure in good agreement with experiments is formed. With respect to sound generation, good agreement with the measured acoustic signal for colliding rings is obtained and a feature previously thought to be due to viscous effects is shown to be an effect of inviscid core deformation alone. For passage interactions, a component of high frequency is present. Evidence for the importance of this noise source in jet noise spectra is provided. Finally, processes of fluid engulfment and rejection for an unsteady vortex ring are studied using the stable and unstable manifolds. The unstable manifold shows excellent agreement with flow visualization experiments for leapfrogging rings suggesting that it may be a good tool for numerical flow visualization in other time periodic flows.

Physics of Regolith Impacts in Microgravity Experiment (PRIME)

NASA Technical Reports Server (NTRS)

Motil, Brian (Technical Monitor); Colwell, Joshua; Sture, S.

2003-01-01

Collisions between planetary ring particles and in some protoplanetary disk environments occur at low impact velocities (v less than 1 m/s) . In some regions of Saturn s rings, for example, the typical collision velocity inferred from observations by the Voyager spacecraft and dynamical modeling is a fraction of a centimeter per second. Although no direct observations of an individual ring particle exist, the abundance of dust in planetary rings and protoplanetary disks suggests that larger ring and disk particles are coated with a layer of smaller particles and dust - the "regolith". Because the ring particles and proto-planetesimals are small (cm to m-sized), the regolith is only weakly bound to the surface by gravity. Similarly, secondary impacts on asteroids by large blocks of ejecta from high velocity cratering events result in low velocity impacts into the asteroid regolith, which is also weakly bound by the asteroid s gravity. At the current epoch and throughout their history, low velocity collisions have played an important role in sculpting planetary systems. In a one-Earth-gravity environment, it is not possible to experimentally determine the behavior of impact eject from such low velocity collisions. Impacts typically occur at speeds exceeding the mutual escape velocity of the two bodies. Thus, impacts at speeds on the order of 10 m/sec or less involve objects that are tens of meters across, or smaller. This research program is an experimental study of such low velocity collisions in a microgravity environment. The experimental work builds on the Collisions Into Dust Experiment (COLLIDE), which has flown twice on the space shuttle. The PRIME experimental apparatus is a new apparatus designed specifically for the environment provided on the NASA KC- 135 reduced gravity aircraft.

Spin Pit Application of Image Derotated Holographic Interferometry.

DTIC Science & Technology

1980-09-01

temperatures resulting from induction heating of the test structuore through the interaction of the electromagnets and the magnetic ring. Subsequent...reference beam, and a Tektronix Model 7633 storage oscilloscope. When the laser is fired, a trigger signal from the laser power supply initiates the...rapid induction heating of the test structure due to the interaction of the electromagnets and the magnetic ring was evi(lent with the switch from dc to

Diagnostic Systems Plan for the Advanced Light Source Top-OffUpgrade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barry, Walter; Chin, Mike; Robin, David

2005-05-10

The Advanced Light Source (ALS) will soon be upgraded to enable top-off operations [1], in which electrons are quasi-continuously injected to produce constant stored beam current. The upgrade is structured in two phases. First, we will upgrade our injector from 1.5 GeV to 1.9 GeV to allow full energy injection and will start top-off operations. In the second phase, we will upgrade the Booster Ring (BR) with a bunch cleaning system to allow high bunch purity top-off injection. A diagnostics upgrade will be crucial for success in both phases of the top-off project, and our plan for it is describedmore » in this paper. New booster ring diagnostics will include updated beam position monitor (BPM) electronics, a tune monitoring system, and a new scraper. Two new synchrotron light monitors and a beam stop will be added to the booster-to-storage ring transfer line (BTS), and all the existing beam current monitors along the accelerator chain will be integrated into a single injection efficiency monitoring application. A dedicated bunch purity monitor will be installed in the storage ring (SR). Together, these diagnostic upgrades will enable smooth commissioning of the full energy injector and a quick transition to high quality top-off operation at the ALS.« less

The cryogenic storage ring CSR

NASA Astrophysics Data System (ADS)

von Hahn, R.; Becker, A.; Berg, F.; Blaum, K.; Breitenfeldt, C.; Fadil, H.; Fellenberger, F.; Froese, M.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; Heber, O.; Herwig, P.; Karthein, J.; Krantz, C.; Kreckel, H.; Lange, M.; Laux, F.; Lohmann, S.; Menk, S.; Meyer, C.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Saurabh, S.; Schippers, S.; Schröter, C. D.; Schwalm, D.; Schweikhard, L.; Sieber, T.; Shornikov, A.; Spruck, K.; Sunil Kumar, S.; Ullrich, J.; Urbain, X.; Vogel, S.; Wilhelm, P.; Wolf, A.; Zajfman, D.

2016-06-01

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm-3 is derived, equivalent to a room-temperature pressure below 10-14 mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

The cryogenic storage ring CSR.

PubMed

von Hahn, R; Becker, A; Berg, F; Blaum, K; Breitenfeldt, C; Fadil, H; Fellenberger, F; Froese, M; George, S; Göck, J; Grieser, M; Grussie, F; Guerin, E A; Heber, O; Herwig, P; Karthein, J; Krantz, C; Kreckel, H; Lange, M; Laux, F; Lohmann, S; Menk, S; Meyer, C; Mishra, P M; Novotný, O; O'Connor, A P; Orlov, D A; Rappaport, M L; Repnow, R; Saurabh, S; Schippers, S; Schröter, C D; Schwalm, D; Schweikhard, L; Sieber, T; Shornikov, A; Spruck, K; Sunil Kumar, S; Ullrich, J; Urbain, X; Vogel, S; Wilhelm, P; Wolf, A; Zajfman, D

2016-06-01

An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremely low. A residual-gas density below 140 cm(-3) is derived, equivalent to a room-temperature pressure below 10(-14) mbar. Fast atomic, molecular, and cluster ion beams stored for long periods of time in a cryogenic environment will allow experiments on collision- and radiation-induced fragmentation processes of ions in known internal quantum states with merged and crossed photon and particle beams.

The insertion device magnetic measurement facility: Prototype and operational procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burkel, L.; Dejus, R.; Maines, J.

1993-03-01

This report is a description of the current status of the magnetic measurement facility and is a basic instructional manual for the operation of the facility and its components. Please refer to the appendices for more detailed information about specific components and procedures. The purpose of the magnetic measurement facility is to take accurate measurements of the magnetic field in the gay of the IDs in order to determine the effect of the ID on the stored particle beam and the emitted radiation. The facility will also play an important role when evaluating new ideas, novel devices, and inhouse prototypesmore » as part of the ongoing research and development program at the APS. The measurements will be performed with both moving search coils and moving Hall probes. The IDs will be evaluated by computer modeling of the emitted radiation for any given (measured) magnetic field map. The quality of the magnetic field will be described in terms of integrated multipoles for the effect on Storage Ring performance and in terms of the derived trajectories for the emitted radiation. Before being installed on the Storage Ring, every device will be measured and characterized to assure that it is compatible with Storage Ring requirements and radiation specifications. The accuracy that the APS needs to achieve for magnetic measurements will be based on these specifications.« less

Magnet design for a low-emittance storage ring

PubMed Central

Johansson, Martin; Anderberg, Bengt; Lindgren, Lars-Johan

2014-01-01

The MAX IV 3 GeV storage ring, currently under construction, pursues the goal of low electron beam emittance by using a multi-bend achromat magnet lattice, which is realised by having several consecutive magnet elements precision-machined out of a common solid iron block, 2.3–3.4 m long. With this magnet design solution, instead of having 1320 individual magnets, the MAX IV 3 GeV storage ring is built up using 140 integrated ‘magnet block’ units, containing all these magnet elements. Major features of this magnet block design are compactness, vibration stability and that the alignment of magnet elements within each unit is given by the mechanical accuracy of the CNC machining rather than individual field measurement and adjustment. This article presents practical engineering details of implementing this magnet design solution, and mechanical + magnetic field measurement results from the magnet production series. At the time of writing (spring 2014), the production series, which is totally outsourced to industry, is roughly half way through, with mechanical/magnetic QA conforming to specifications. It is the conclusion of the authors that the MAX IV magnet block concept, which has sometimes been described as new or innovative, is from a manufacturing point of view simply a collection of known mature production methods and measurement procedures, which can be executed at fixed cost with a low level of risk. PMID:25177980

Code comparison for accelerator design and analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsa, Z.

1988-01-01

We present a comparison between results obtained from standard accelerator physics codes used for the design and analysis of synchrotrons and storage rings, with programs SYNCH, MAD, HARMON, PATRICIA, PATPET, BETA, DIMAD, MARYLIE and RACE-TRACK. In our analysis we have considered 5 (various size) lattices with large and small angles including AGS Booster (10/degree/ bend), RHIC (2.24/degree/), SXLS, XLS (XUV ring with 45/degree/ bend) and X-RAY rings. The differences in the integration methods used and the treatment of the fringe fields in these codes could lead to different results. The inclusion of nonlinear (e.g., dipole) terms may be necessary inmore » these calculations specially for a small ring. 12 refs., 6 figs., 10 tabs.« less

TSR: A storage and cooling ring for HIE-ISOLDE

NASA Astrophysics Data System (ADS)

Butler, P. A.; Blaum, K.; Davinson, T.; Flanagan, K.; Freeman, S. J.; Grieser, M.; Lazarus, I. H.; Litvinov, Yu. A.; Lotay, G.; Page, R. D.; Raabe, R.; Siesling, E.; Wenander, F.; Woods, P. J.

2016-06-01

It is planned to install the heavy-ion, low-energy ring TSR, currently at the Max-Planck-Institute for Nuclear Physics in Heidelberg, at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored, cooled secondary beams that is rich and varied, spanning from studies of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. In addition to experiments performed using beams recirculating within the ring, the cooled beams can be extracted and exploited by external spectrometers for high-precision measurements. The capabilities of the ring facility as well as some physics cases will be presented, together with a brief report on the status of the project.

The Case for Massive and Ancient Rings of Saturn

NASA Astrophysics Data System (ADS)

Esposito, Larry W.

2016-04-01

Analysis of Voyager and Pioneer 11 results give a mass for Saturn's rings, M = 5 x 10-8 Msat. This is about the mass of Saturn's small moon Mimas. This has been interpreted as a lower limit to the ring mass (Esposito et al 1983), since the thickest parts of the rings were not penetrated by the stellar occultstion, and this calculation assumes an unvarying particle size throughout the rings. Because the rings are constantly bombarded by micrometeroids, their current composition of nearly pure water ice implies such low mass rings must have formed recently. The case is par-ticularly strong for Saturn's A ring, where the data are the best, implying the A ring is less than 10% of the age of the Saturn (Esposito 1986). Cassini results com-pound this problem. UVIS spectra are consistent with either young rings or rings about 10x as massive as the Voyager estimate (Elliott and Esposito (2011). CDA confirms the impacting mass flux is similar to that as-sumed for the pollution calculations (Kempf etal 2015). VIMS analysis of density wave signatures in the B ring gives a value of about 1/3 the Voyager value (Hedmann etal 2016). This VIMS result implies the rings are even younger! The problem is that young rings are very unlikely to be formed recently, meaning that we live in a very special epoch, following some unlikely recent origin… like disruption of a medium sized moon or capture of the fragments of a disrupted comet. This paradox (Charnoz etal 2009) is unre-solved. Alternative interpretations: To take the VIMS results at face value, Saturn's low mass rings must be very young. The optically thick B ring must be made of small, porous or fractal particles. This is hard to understand, since the particles are continually colliding every few hours and temporary aggregates will stir the collision velocities to higher values. An alternative is that we accept the higher mass interpretation of the Pioneer 11 results (Esposito etal 2008) using the granola bar model of Colwell etal 2007. This would imply that the density wave structure seen by VIMS is not sensing all the mass in the rings, where structure near strong resonances is dominted by temporary aggregates, and where non-linear effects cause the parti-cles to jam (Lewis and Stewart 2009). The density waves may be seeing the mass density in the gaps be-tween self-gravity wakes, whose optical depth is roughly contant and considerably lower than the total B ring opacity (Colwell etal 2007). These massive rings would be consistent with the origin model of Canup (2011) where a Titan-sized diffferntiated moon was disrupted early in Saturn's formation.

Development and operating experience of a 1.1-m-long superconducting undulator at the Advanced Photon Source

DOE PAGES

Ivanyushenkov, Y.; Harkay, K.; Borland, M.; ...

2017-10-03

Development of superconducting undulators continues at the Advanced Photon Source (APS). Two years after successful installation and commissioning of the first relatively short superconducting undulator “SCU0” in Sector 6 of the APS storage ring, the second 1.1-m long superconducting undulator “SCU1” was installed in Sector 1 of the APS. The device has been in user operation since its commissioning in May 2015. This paper describes the magnetic and cryogenic design of the SCU1 together with the results of stand-alone cold tests. The SCU1’s magnetic and cryogenic performance as well as its operating experience in the APS storage ring are alsomore » presented.« less

Coupling control and optimization at the Canadian Light Source

NASA Astrophysics Data System (ADS)

Wurtz, W. A.

2018-06-01

We present a detailed study using the skew quadrupoles in the Canadian Light Source storage ring lattice to control the parameters of a coupled lattice. We calculate the six-dimensional beam envelop matrix and use it to produce a variety of objective functions for optimization using the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm. MOPSO produces a number of skew quadrupole configurations that we apply to the storage ring. We use the X-ray synchrotron radiation diagnostic beamline to image the beam and we make measurements of the vertical dispersion and beam lifetime. We observe satisfactory agreement between the measurements and simulations. These methods can be used to adjust phase space coupling in a rational way and have applications to fine-tuning the vertical emittance and Touschek lifetime and measuring the gas scattering lifetime.

The development of enabling technologies for producing active interrogation beams.

PubMed

Kwan, Thomas J T; Morgado, Richard E; Wang, Tai-Sen F; Vodolaga, B; Terekhin, V; Onischenko, L M; Vorozhtsov, S B; Samsonov, E V; Vorozhtsov, A S; Alenitsky, Yu G; Perpelkin, E E; Glazov, A A; Novikov, D L; Parkhomchuk, V; Reva, V; Vostrikov, V; Mashinin, V A; Fedotov, S N; Minayev, S A

2010-10-01

A U.S./Russian collaboration of accelerator scientists was directed to the development of high averaged-current (∼1 mA) and high-quality (emittance ∼15 πmm mrad; energy spread ∼0.1%) 1.75 MeV proton beams to produce active interrogation beams that could be applied to counterterrorism. Several accelerator technologies were investigated. These included an electrostatic tandem accelerator of novel design, a compact cyclotron, and a storage ring with energy compensation and electron cooling. Production targets capable of withstanding the beam power levels were designed, fabricated, and tested. The cyclotron/storage-ring system was theoretically studied and computationally designed, and the electrostatic vacuum tandem accelerator at BINP was demonstrated for its potential in active interrogation of explosives and special nuclear materials.

Prospects of high-resolution resonant X-ray inelastic scattering studies on solid materials, liquids and gases at diffraction-limited storage rings

PubMed Central

Schmitt, Thorsten; de Groot, Frank M. F.; Rubensson, Jan-Erik

2014-01-01

The spectroscopic technique of resonant inelastic X-ray scattering (RIXS) will particularly profit from immensely improved brilliance of diffraction-limited storage rings (DLSRs). In RIXS one measures the intensities of excitations as a function of energy and momentum transfer. DLSRs will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size to new limits. With RIXS one nowadays probes a broad range of electronic systems reaching from simple molecules to complex materials displaying phenomena like peculiar magnetism, two-dimensional electron gases, superconductivity, photovoltaic energy conversion and heterogeneous catalysis. In this article the types of improved RIXS studies that will become possible with X-ray beams from DLSRs are envisioned. PMID:25177995

Development and operating experience of a 1.1-m-long superconducting undulator at the Advanced Photon Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanyushenkov, Y.; Harkay, K.; Borland, M.

Development of superconducting undulators continues at the Advanced Photon Source (APS). Two years after successful installation and commissioning of the first relatively short superconducting undulator “SCU0” in Sector 6 of the APS storage ring, the second 1.1-m long superconducting undulator “SCU1” was installed in Sector 1 of the APS. The device has been in user operation since its commissioning in May 2015. This paper describes the magnetic and cryogenic design of the SCU1 together with the results of stand-alone cold tests. The SCU1’s magnetic and cryogenic performance as well as its operating experience in the APS storage ring are alsomore » presented.« less

Time domain analysis of coherent terahertz synchrotron radiation

NASA Astrophysics Data System (ADS)

Hübers, H.-W.; Semenov, A.; Holldack, K.; Schade, U.; Wüstefeld, G.; Gol'tsman, G.

2005-10-01

The time structure of coherent terahertz synchrotron radiation at the electron storage ring of the Berliner Elektronensynchrotron und Speicherring Gesellschaft has been analyzed with a fast superconducting hot-electron bolometer. The emission from a single bunch of electrons was found to last ˜1500ps at frequencies around 0.4THz, which is much longer than the length of an electron bunch in the time domain (˜5ps). It is suggested that this is caused by multiple reflections at the walls of the beam line. The quadratic increase of the power with the number of electrons in the bunch as predicted for coherent synchrotron radiation and the transition from stable to bursting radiation were determined from a single storage ring fill pattern of bunches with different populations.

Recent Results With Coupled Opto-Electronic Oscillators

NASA Astrophysics Data System (ADS)

Yao, X. S.; Maleki, L.; Wu, C.; Davis, L.; Forouhar, S.

1998-07-01

We present experimental results of coupled opto-electronic oscillators (COEOs) constructed with a semiconductor optical-amplifier-based ring laser, a semiconductor Fabry-Perot laser, and a semiconductor colliding-pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices, we obtained optical pulses as short as 6 ps and RF signals as high in frequency as 18 GHz with a spectral purity comparable to an HP 8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals.

Recent results with the coupled opto-electronic oscillator

NASA Astrophysics Data System (ADS)

Yao, X. S.; Maleki, Lute; Wu, Chi; Davis, Lawrence J.; Forouhar, Siamak

1998-11-01

We present experimental results of coupled opto-electronic oscillators (COEO) constructed with a semiconductor optical amplifier based ring laser, a semiconductor Fabry-Perot laser, and a semiconductor colliding pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices, we obtained optical pulses as short as 6 picoseconds and RF signals as high in frequency as 18 GHz with a spectral purity comparable with a HP8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals.

Robert R. Wilson Prize III: Applications of Intrabeam Scattering Formulae to a Myriad of Accelerator Systems

NASA Astrophysics Data System (ADS)

Mtingwa, Sekazi K.

2017-01-01

We discuss our entree into accelerator physics and the problem of intrabeam scattering in particular. We focus on the historical importance of understanding intrabeam scattering for the successful operation of Fermilab's Accumulator and Tevatron and the subsequent hunt for the top quark, and its importance for successful operation of CERN's Large Hadron Collider that discovered the Higgs boson. We provide details on intrabeam scattering formalisms for hadron and electron beams at high energies, concluding with an Ansatz by Karl Bane that has applications to electron damping rings and synchrotron light sources.

Ring Around the Black Hole

NASA Technical Reports Server (NTRS)

Wanjek, Christopher

2003-01-01

Regardless of size, black holes easily acquire accretion disks. Supermassive black holes can feast on the bountiful interstellar gas in galactic nuclei. Small black holes formed from collapsing stars often belong to binary systems in which a bulging companion star can spill some of its gas into the black hole s reach. In the chaotic mess of the accretion disk, atoms collide with one another. Swirling plasma reaches speeds upward of 10% that of light and glows brightly in many wavebands, particularly in X-rays. Gas gets blown back by a wind of radiation from the inner disk. New material enters the disks from different directions.

Design of barrier bucket kicker control system

NASA Astrophysics Data System (ADS)

Ni, Fa-Fu; Wang, Yan-Yu; Yin, Jun; Zhou, De-Tai; Shen, Guo-Dong; Zheng, Yang-De.; Zhang, Jian-Chuan; Yin, Jia; Bai, Xiao; Ma, Xiao-Li

2018-05-01

The Heavy-Ion Research Facility in Lanzhou (HIRFL) contains two synchrotrons: the main cooler storage ring (CSRm) and the experimental cooler storage ring (CSRe). Beams are extracted from CSRm, and injected into CSRe. To apply the Barrier Bucket (BB) method on the CSRe beam accumulation, a new BB technology based kicker control system was designed and implemented. The controller of the system is implemented using an Advanced Reduced Instruction Set Computer (RISC) Machine (ARM) chip and a field-programmable gate array (FPGA) chip. Within the architecture, ARM is responsible for data presetting and floating number arithmetic processing. The FPGA computes the RF phase point of the two rings and offers more accurate control of the time delay. An online preliminary experiment on HIRFL was also designed to verify the functionalities of the control system. The result shows that the reference trigger point of two different sinusoidal RF signals for an arbitrary phase point was acquired with a matched phase error below 1° (approximately 2.1 ns), and the step delay time better than 2 ns were realized.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plogmaker, Stefan; Johansson, Erik M. J.; Rensmo, Haakan

A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of {approx}8 to {approx}120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses ormore » pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.« less

Fabrication and test of model superconducting inflector for g-2 at FNAL

DOE PAGES

Krave, Steven; Kashikhin, Vladimir S.; Strauss, Thomas

2017-03-01

The new FNAL g-2 experiment is based on the muon storage ring previously used at BNL. The 1.45 T dipole magnetic field in the storage ring is required to have very high (1 ppm) homogeneity. The muon beam injected into the ring must be transported through the magnet yoke and the main superconducting coil cryostat with minimal distortions. The old inflector magnet shielded the main dipole fringe field inside the muon transport beam pipe, with an outer NbTi superconducting screen, and did not disturb the field in the area of circulating beam. Nevertheless, this magnet had coils with closed endsmore » in which a large fraction of muon beam particles were lost. A new magnet is envisioned utilizing the same cross section as the original with open ends for improved beam transport. A model magnet has been wound utilizing 3d printed parts to verify the magnetic behavior of the magnet at room temperature and validate winding of the complicated geometry required for the magnet ends. Finally, room temperature magnetic measurements have been performed and confirm the magnetic design« less

Electron molecular ion recombination: product excitation and fragmentation.

PubMed

Adams, Nigel G; Poterya, Viktoriya; Babcock, Lucia M

2006-01-01

Electron-ion dissociative recombination is an important ionization loss process in any ionized gas containing molecular ions. This includes the interstellar medium, circumstellar shells, cometary comae, planetary ionospheres, fusion plasma boundaries, combustion flames, laser plasmas and chemical deposition and etching plasmas. In addition to controlling the ionization density, the process generates many radical species, which can contribute to a parallel neutral chemistry. Techniques used to obtain rate data and product information (flowing afterglows and storage rings) are discussed and recent data are reviewed including diatomic to polyatomic ions and cluster ions. The data are divided into rate coefficients and cross sections, including their temperature/energy dependencies, and quantitative identification of neutral reaction products. The latter involve both ground and electronically excited states and including vibrational excitation. The data from the different techniques are compared and trends in the data are examined. The reactions are considered in terms of the basic mechanisms (direct and indirect processes including tunneling) and recent theoretical developments are discussed. Finally, new techniques are mentioned (for product identification; electrostatic storage rings, including single and double rings; Coulomb explosion) and new ways forward are suggested.

9975 Shipping package component long-term degradation rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daugherty, W. L.

Special nuclear materials are being stored in the K-Area Complex using 3013 containers that are held within Model 9975 shipping packages. The service life for these packages in storage was recently increased from 15 to 20 years, since some of these packages have been stored for nearly 15 years. A strategy is also being developed whereby such storage might be extended beyond 20 years. This strategy is based on recent calculations that support acceptable 9975 package performance for 20 years with internal heat loads up to 19 watts, and identifies a lower heat load limit for which the package componentsmore » should degrade at half the bounding rate or less, thus doubling the effective storage life for these lower wattage packages. The components of the 9975 package that are sensitive to aging under storage conditions are the fiberboard overpack and the O-ring seals, although some degradation of the lead shield and outer drum are also possible. This report summarizes degradation rates applicable to lower heat load storage conditions. In particular, the O-ring seals should provide leak-tight performance for more than 40 years in packages for which their maximum temperature is ≤135 °F. Similarly, the fiberboard should remain acceptable in performance of its required safety functions for up to 40 years in packages with a maximum fiberboard temperature ≤125 °F.« less

Hawaii Energy and Environmental Technologies Initiative 2010 (HEET10)

DTIC Science & Technology

2016-09-30

illustrated how local battery storage support of the lOMW Hawi wind farm can cause grid-wide issues. However, it was found that battery cycling can...capabilities pertaining to three different ex situ diagnostics were acquired and used under HEETlO. Focus was given to the catalyst (rotating ring ...cell. These capabilities are illustrated in Figure 9 1.1.1. Figure 1.1.1: (left) rotating ring /disc electrode; (middle) membrane conductivity cell

A FODO racetrack ring for nuSTORM: design and optimization

DOE PAGES

Liu, A.; Bross, A.; Neuffer, D.

2017-07-17

Here, the goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ~ 480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize themore » arc length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.« less

Storage element performance optimization for CMS analysis jobs

NASA Astrophysics Data System (ADS)

Behrmann, G.; Dahlblom, J.; Guldmyr, J.; Happonen, K.; Lindén, T.

2012-12-01

Tier-2 computing sites in the Worldwide Large Hadron Collider Computing Grid (WLCG) host CPU-resources (Compute Element, CE) and storage resources (Storage Element, SE). The vast amount of data that needs to processed from the Large Hadron Collider (LHC) experiments requires good and efficient use of the available resources. Having a good CPU efficiency for the end users analysis jobs requires that the performance of the storage system is able to scale with I/O requests from hundreds or even thousands of simultaneous jobs. In this presentation we report on the work on improving the SE performance at the Helsinki Institute of Physics (HIP) Tier-2 used for the Compact Muon Experiment (CMS) at the LHC. Statistics from CMS grid jobs are collected and stored in the CMS Dashboard for further analysis, which allows for easy performance monitoring by the sites and by the CMS collaboration. As part of the monitoring framework CMS uses the JobRobot which sends every four hours 100 analysis jobs to each site. CMS also uses the HammerCloud tool for site monitoring and stress testing and it has replaced the JobRobot. The performance of the analysis workflow submitted with JobRobot or HammerCloud can be used to track the performance due to site configuration changes, since the analysis workflow is kept the same for all sites and for months in time. The CPU efficiency of the JobRobot jobs at HIP was increased approximately by 50 % to more than 90 %, by tuning the SE and by improvements in the CMSSW and dCache software. The performance of the CMS analysis jobs improved significantly too. Similar work has been done on other CMS Tier-sites, since on average the CPU efficiency for CMSSW jobs has increased during 2011. Better monitoring of the SE allows faster detection of problems, so that the performance level can be kept high. The next storage upgrade at HIP consists of SAS disk enclosures which can be stress tested on demand with HammerCloud workflows, to make sure that the I/O-performance is good.

Simulation of Crab Waist Collisions In DA$$\\Phi$$NE With KLOE-2 Interaction Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zobov, M.; Drago, A.; Gallo, A.

2015-06-24

After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentiallymore » achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e- ring working point was implemented and resulted in a significant performance increase.« less

Measurement of pion, kaon and proton production in proton-proton collisions at [Formula: see text] TeV.

PubMed

Adam, J; Adamová, D; Aggarwal, M M; Rinella, G Aglieri; Agnello, M; Agrawal, N; Ahammed, Z; Ahmed, I; Ahn, S U; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Alam, S N; Aleksandrov, D; Alessandro, B; Alexandre, D; Molina, R Alfaro; Alici, A; Alkin, A; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Prado, C Alves Garcia; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldisseri, A; Ball, M; Pedrosa, F Baltasar Dos Santos; Baral, R C; Barbano, A M; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartalini, P; Bartke, J; Bartsch, E; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Camejo, A Batista; Batyunya, B; Batzing, P C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Martinez, H Bello; Bellwied, R; Belmont, R; Belmont-Moreno, E; Belyaev, V; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhat, I R; Bhati, A K; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Biswas, S; Bjelogrlic, S; Blanco, F; Blau, D; Blume, C; Bock, F; Bogdanov, A; Bøggild, H; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Borri, M; Bossú, F; Botje, M; Botta, E; Böttger, S; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Brucken, E J; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Buxton, J T; Caffarri, D; Cai, X; Caines, H; Diaz, L Calero; Caliva, A; Villar, E Calvo; Camerini, P; Carena, F; Carena, W; Castellanos, J Castillo; Castro, A J; Casula, E A R; Cavicchioli, C; Sanchez, C Ceballos; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Chartier, M; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Chelnokov, V; Cherney, M; Cheshkov, C; Cheynis, B; Barroso, V Chibante; Chinellato, D D; Chochula, P; Choi, K; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Balbastre, G Conesa; Valle, Z Conesa Del; Connors, M E; Contreras, J G; Cormier, T M; Morales, Y Corrales; Maldonado, I Cortés; Cortese, P; Cosentino, M R; Costa, F; Crochet, P; Albino, R Cruz; Cuautle, E; Cunqueiro, L; Dahms, T; Dainese, A; Danu, A; Das, D; Das, I; Das, S; Dash, A; Dash, S; De, S; Caro, A De; Cataldo, G de; Cuveland, J de; Falco, A De; Gruttola, D De; Marco, N De; Pasquale, S De; Deisting, A; Deloff, A; Dénes, E; D'Erasmo, G; Bari, D Di; Mauro, A Di; Nezza, P Di; Corchero, M A Diaz; Dietel, T; Dillenseger, P; Divià, R; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Gimenez, D Domenicis; Dönigus, B; Dordic, O; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Ehlers, R J; Elia, D; Engel, H; Erazmus, B; Erhardt, F; Eschweiler, D; Espagnon, B; Estienne, M; Esumi, S; Eum, J; Evans, D; Evdokimov, S; Eyyubova, G; Fabbietti, L; Fabris, D; Faivre, J; Fantoni, A; Fasel, M; Feldkamp, L; Felea, D; Feliciello, A; Feofilov, G; Ferencei, J; Téllez, A Fernández; Ferreiro, E G; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Fleck, M G; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Furs, A; Girard, M Fusco; Gaardhøje, J J; Gagliardi, M; Gago, A M; Gallio, M; Gangadharan, D R; Ganoti, P; Gao, C; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Gasik, P; Germain, M; Gheata, A; Gheata, M; Ghosh, P; Ghosh, S K; Gianotti, P; Giubellino, P; Giubilato, P; Dziadus, E Gladysz; Glässel, P; Ramirez, A Gomez; Zamora, P González; Gorbunov, S; Görlich, L; Gotovac, S; Grabski, V; Graczykowski, L K; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Gulbrandsen, K; Gulkanyan, H; Gunji, T; Gupta, A; Gupta, R; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Hartmann, H; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Corral, G Herrera; Hess, B A; Hetland, K F; Hilden, T E; Hillemanns, H; Hippolyte, B; Hristov, P; Huang, M; Humanic, T J; Hussain, N; Hussain, T; Hutter, D; Hwang, D S; Ilkaev, R; Ilkiv, I; Inaba, M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, M; Ivanov, V; Izucheev, V; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, C; Jena, S; Bustamante, R T Jimenez; Jones, P G; Jung, H; Jusko, A; Kalinak, P; Kalweit, A; Kamin, J; Kang, J H; Kaplin, V; Kar, S; Uysal, A Karasu; Karavichev, O; Karavicheva, T; Karpechev, E; Kebschull, U; Keidel, R; Keijdener, D L D; Keil, M; Khan, K H; Khan, M M; Khan, P; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, B; Kim, D W; Kim, D J; Kim, H; Kim, J S; Kim, M; Kim, M; Kim, S; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, C; Klein, J; Klein-Bösing, C; Kluge, A; Knichel, M L; Knospe, A G; Kobayashi, T; Kobdaj, C; Kofarago, M; Köhler, M K; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Kondratyuk, E; Konevskikh, A; Kouzinopoulos, C; Kovalenko, O; Kovalenko, V; Kowalski, M; Kox, S; Meethaleveedu, G Koyithatta; Kral, J; Králik, I; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Kryshen, E; Krzewicki, M; Kubera, A M; Kučera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kumar, L; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kweon, M J; Kwon, Y; Pointe, S L La; Rocca, P La; Fernandes, C Lagana; Lakomov, I; Langoy, R; Lara, C; Lardeux, A; Lattuca, A; Laudi, E; Lea, R; Leardini, L; Lee, G R; Lee, S; Legrand, I; Lehnert, J; Lemmon, R C; Lenti, V; Leogrande, E; Monzón, I León; Leoncino, M; Lévai, P; Li, S; Li, X; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Loizides, C; Lopez, X; Torres, E López; Lowe, A; Lu, X-G; Luettig, P; Lunardon, M; Luparello, G; Maevskaya, A; Mager, M; Mahajan, S; Mahmood, S M; Maire, A; Majka, R D; Malaev, M; Cervantes, I Maldonado; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Manko, V; Manso, F; Manzari, V; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Margutti, J; Marín, A; Markert, C; Marquard, M; Martin, N A; Blanco, J Martin; Martinengo, P; Martínez, M I; Martínez García, G; Pedreira, M Martinez; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Masui, H; Matyja, A; Mayer, C; Mazer, J; Mazzoni, M A; Mcdonald, D; Meddi, F; Menchaca-Rocha, A; Meninno, E; Pérez, J Mercado; Meres, M; Miake, Y; Mieskolainen, M M; Mikhaylov, K; Milano, L; Milosevic, J; Minervini, L M; Mischke, A; Mishra, A N; Miśkowiec, D; Mitra, J; Mitu, C M; Mohammadi, N; Mohanty, B; Molnar, L; Zetina, L Montaño; Montes, E; Morando, M; Godoy, D A Moreira De; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Mühlheim, D; Muhuri, S; Mukherjee, M; Müller, H; Mulligan, J D; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Naru, M U; Nattrass, C; Nayak, K; Nayak, T K; Nazarenko, S; Nedosekin, A; Nellen, L; Ng, F; Nicassio, M; Niculescu, M; Niedziela, J; Nielsen, B S; Nikolaev, S; Nikulin, S; Nikulin, V; Noferini, F; Nomokonov, P; Nooren, G; Norman, J; Nyanin, A; Nystrand, J; Oeschler, H; Oh, S; Oh, S K; Ohlson, A; Okatan, A; Okubo, T; Olah, L; Oleniacz, J; Silva, A C Oliveira Da; Oliver, M H; Onderwaater, J; Oppedisano, C; Velasquez, A Ortiz; Oskarsson, A; Otwinowski, J; Oyama, K; Ozdemir, M; Pachmayer, Y; Pagano, P; Paić, G; Pajares, C; Pal, S K; Pan, J; Pandey, A K; Pant, D; Papikyan, V; Pappalardo, G S; Pareek, P; Park, W J; Parmar, S; Passfeld, A; Paticchio, V; Paul, B; Pawlak, T; Peitzmann, T; Costa, H Pereira Da; Filho, E Pereira De Oliveira; Peresunko, D; Lara, C E Pérez; Peskov, V; Pestov, Y; Petráček, V; Petrov, V; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Piyarathna, D B; Płoskoń, M; Planinic, M; Pluta, J; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Polichtchouk, B; Poljak, N; Poonsawat, W; Pop, A; Porteboeuf-Houssais, S; Porter, J; Pospisil, J; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puccio, M; Puddu, G; Pujahari, P; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Raha, S; Rajput, S; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, R; Raniwala, S; Räsänen, S S; Rascanu, B T; Rathee, D; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Ren, X; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riabov, V; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Ristea, C; Rivetti, A; Rocco, E; Cahuantzi, M Rodríguez; Manso, A Rodriguez; Røed, K; Rogochaya, E; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Ronflette, L; Rosnet, P; Rossi, A; Roukoutakis, F; Roy, A; Roy, C; Roy, P; Montero, A J Rubio; Rui, R; Russo, R; Ryabinkin, E; Ryabov, Y; Rybicki, A; Sadovsky, S; Šafařík, K; Sahlmuller, B; Sahoo, P; Sahoo, R; Sahoo, S; Sahu, P K; Saini, J; Sakai, S; Saleh, M A; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Castro, X Sanchez; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Seeder, K S; Seger, J E; Sekiguchi, Y; Selyuzhenkov, I; Senosi, K; Seo, J; Serradilla, E; Sevcenco, A; Shabanov, A; Shabetai, A; Shadura, O; Shahoyan, R; Shangaraev, A; Sharma, A; Sharma, N; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Sielewicz, K M; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Simonetti, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Slupecki, M; Smirnov, N; Snellings, R J M; Snellman, T W; Søgaard, C; Soltz, R; Song, J; Song, M; Song, Z; Soramel, F; Sorensen, S; Spacek, M; Spiriti, E; Sputowska, I; Stassinaki, M Spyropoulou; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Strmen, P; Suaide, A A P; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Šumbera, M; Symons, T J M; Szabo, A; Toledo, A Szanto de; Szarka, I; Szczepankiewicz, A; Szymanski, M; Takahashi, J; Tanaka, N; Tangaro, M A; Takaki, J D Tapia; Peloni, A Tarantola; Tariq, M; Tarzila, M G; Tauro, A; Muñoz, G Tejeda; Telesca, A; Terasaki, K; Terrevoli, C; Teyssier, B; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Toia, A; Trogolo, S; Trubnikov, V; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ullaland, K; Uras, A; Usai, G L; Utrobicic, A; Vajzer, M; Vala, M; Palomo, L Valencia; Vallero, S; Maarel, J Van Der; Hoorne, J W Van; Leeuwen, M van; Vanat, T; Vyvre, P Vande; Varga, D; Vargas, A; Vargyas, M; Varma, R; Vasileiou, M; Vasiliev, A; Vauthier, A; Vechernin, V; Veen, A M; Veldhoen, M; Velure, A; Venaruzzo, M; Vercellin, E; Limón, S Vergara; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Baillie, O Villalobos; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Vislavicius, V; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; Haller, B von; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, J; Wang, H; Wang, M; Wang, Y; Watanabe, D; Weber, M; Weber, S G; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yano, S; Yasnopolskiy, S; Yin, Z; Yokoyama, H; Yoo, I-K; Yurchenko, V; Yushmanov, I; Zaborowska, A; Zaccolo, V; Zaman, A; Zampolli, C; Zanoli, H J C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zgura, I S; Zhalov, M; Zhang, H; Zhang, X; Zhang, Y; Zhao, C; Zhigareva, N; Zhou, D; Zhou, Y; Zhou, Z; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zimmermann, M B; Zinovjev, G; Zyzak, M

The measurement of primary [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production at mid-rapidity ([Formula: see text] 0.5) in proton-proton collisions at [Formula: see text][Formula: see text] 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/[Formula: see text] for pions, from 0.2 up to 6 GeV/[Formula: see text] for kaons and from 0.3 up to 6 GeV/[Formula: see text] for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

A field-cancellation algorithm for constructing economical planar permanent magnet (PM) multipoles with large high-quality field apertures

NASA Astrophysics Data System (ADS)

Tatchyn, Roman

1997-05-01

In recent years studies have been initiated on a new class of multipole field generators consisting of cuboid planar permanent magnet (PM) pieces arranged in bi-planar arrays of 2-fold rotational symmetry(R. Tatchyn, "Planar Permanent Magnet Multipoles: for Particle Accelerator and Storage Ring Applications ," IEEE Trans. Mag. 30, 5050(1994).)(T. Cremer, R. Tatchyn, "Planar Permanent Magnet Multipoles: Measurements and Configurations," in Proceedings of the 1995 Particle Accelerator Conference, IEEE Catalog No. 95CH35843, paper FAQ-20.). These structures, first introduced for Free Electron Laser (FEL) applications(R. Tatchyn, "Selected applications of planar permanent magnet multipoles in FEL insertion device design," NIM A341, 449(1994).), are based on reducing the rotational symmetry of conventional N-pole field generators from N-fold to 2-fold. One consequence of this reduction is a large higher-multipole content in a planar PM multipole's field at distances relatively close to the structure's axis, making it generally unsuitable for applications requiring a large high-quality field aperture. In this paper we outline an economical field-cancellation algorithm that can substantially decrease the harmonic content of a planar PM's field without breaking its biplanar geometry or 2-fold rotational symmetry. This will enable planar PM multipoles to be employed in a broader range of applications than heretofore possible, in particular as distributed focusing elements installed in insertion device gaps on synchrotron storage rings. This accomplishment is expected to remove the conventional restriction of an insertion device's length to the scale of the local focusing beta, enabling short-period, small-gap undulators to be installed and operated as high-brightness sources on lower-energy storage rings(R. Tatchyn, P. Csonka, A. Toor, "Perspectives on micropole undulators in synchrotron radiation technology," Rev. Sci. Instrum. 60(7), 1796(1989).). Operation as ordinary focusing elements in storage ring magnetic lattices, as well as the performance of other high-quality multipole applications, should also becomes possible with the realization of the proposed structures.

ACCELERATORS: RF system design and measurement of HIRF-CSRe

NASA Astrophysics Data System (ADS)

Xu, Zhe; Zhao, Hong-Wei; Wang, Chun-Xiao; Xia, Jia-Wen; Zhan, Wen-Long; Bian, Zhi-Bin

2009-05-01

An RF system for the CSRe (cooling storage experimental ring) is designed and manufactured domestically. The present paper mainly describes the RF system design in five main sections: ferrite ring, RF cavity, RF generator, low level system and cavity cooling. The cavity is based on a type of coaxial resonator which is shorted at the end with one gap and loaded with domestic ferrite rings. The RF generator is designed in the push-pull mode and the low level control system is based on a DSP+FGPA+DDS+USB interface and has three feedback loops. Finally we give the results of the measurement on our system.

Tunable optical analog to electromagnetically induced transparency in graphene-ring resonators system.

PubMed

Wang, Yonghua; Xue, Chenyang; Zhang, Zengxing; Zheng, Hua; Zhang, Wendong; Yan, Shubin

2016-12-12

The analogue of electromagnetically induced transparency in optical ways has shown great potential in optical delay and quantum-information technology due to its flexible design and easy implementation. The chief drawback for these devices is the bad tunability. Here we demonstrate a tunable optical transparency system formed by graphene-silicon microrings which could control the transparent window by electro-optical means. The device consists of cascaded coupled ring resonators and a graphene/graphene capacitor which integrated on one of the rings. By tuning the Fermi level of the graphene sheets, we can modulate the round-trip ring loss so that the transparency window can be dynamically tuned. The results provide a new method for the manipulation and transmission of light in highly integrated optical circuits and quantum information storage devices.

DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

HE,P.; HSEUH,H.C.; MAPES,M.

2001-06-18

The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with {approximately}100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent resultsmore » were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented.« less

Simulation of emittance dilution in electron storage ring from Compton backscattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumberg, L.N.; Blum, E.

1993-07-01

A Monte-Carlo simulation of Compton backscattered {kappa}{sub L}=3.2-{mu}m photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of {Delta}{sub E}=11.9-keV for a sample of 10{sup 7} single scattering events. Electrons are sampled from a beam of natural energy spread {sigma}{sub E} = 5.6-keV and damped transverse angle spreads {sigma}{sub x}{prime}, = .041-mrad and {sigma}{sub y}{prime} = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered X-Rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performedmore » in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads {sigma}{sub xo}=.102-mm, {sigma}{sub x{prime}o}=.041-mrad, {sigma}{sub yo}=.018-mm, {sigma}{sub y{prime}o}=.052-mrad, {sigma}{sub {phi}o}=22-mrad and {sigma}{sub Eo}=6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of f{sub rf}=211.54-MHz and peak voltage V{sub m}=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of {Delta}{sub E} = 124-keV. The transverse widths are only slightly increased from their original values, i.e. {Delta}{sub x} = .106-mm and {Delta}{sub x}{prime}=.043 mrad. The scaled energy spread of {Delta}{sub E} {approximately} 360-keV for {approximately} 350,000 turns desired in a 10-msec X-Ray angiography exposure is well within the RF bucket used here; even V{sub m} < 50-kV is adequate. Further, the electron energy spread adds a negligible RMS X-Ray energy spread of {Delta}{sub Ex}=.32-keV. The electron energy damping time of {tau}{sub E}=379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off of the ring between heart cycles.« less

The Status of Turkish Accelerator Center Test Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yavas, Oe.

2007-04-23

Recently, conceptual design of Turkic Accelerator Center (TAC) proposal was completed. Main goal of this proposal is a charm factory that consists of a linac-ring type electron-positron collider. In addition, synchrotron radiation from the positron ring and free electron laser from the electron linac are proposed. The project related with this proposal has been accepted by Turkish government. It is planned that the Technical Design Report of TAC will have been written in next three years. In this period, an infrared oscillator free electron laser (IR FEL) will be constructed as a test facility for TAC. 20 and 50 MeVmore » electron energies will be used to obtain infra red free electron laser. The main parameters of the electron linac, the optical cavities and the free electron laser were determined. The possible use of obtained laser beam in basic and applied research areas such as biotechnology, nanotechnology, semiconductors and photo chemistry were stated.« less

100 km CEPC parameters and lattice design

NASA Astrophysics Data System (ADS)

Wang, D.; Gao, J.; Yu, C. H.; Zhang, Y.; Wang, Y. W.; Su, F.; Y Zhai, J.; Bai, S.; Geng, H. P.; Bian, T. J.; Wang, N.; Cui, X. H.; Zhang, C.; Qin, Q.

2017-07-01

The 100km double ring configuration with shared superconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z experiment. The luminosity for Z is designed at the level of 1035 cm-2s-1. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced. Work supported by the National Key Programme for S&T Research and Development (Grant NO. 2016YFA0400400) and the National Natural Science Foundation of China (11505198, 11575218, 11605210 and 11605211).

The Large Hadron Collider, a personal recollection

NASA Astrophysics Data System (ADS)

Evans, Lyndon

2014-03-01

The construction of the Large Hadron Collider (LHC) has been a massive endeavor spanning almost 30 years from conception to commissioning. Building the machine with the highest possible energy (7 TeV) in the existing LEP tunnel of 27 km circumference and with a tunnel diameter of only 3.8 m has required considerable innovation. The first was the development of an idea first proposed by Bob Palmer at Brookhaven National Laboratory in 1978, where the two rings are integrated into a single magnetic structure. This compact 2-in-1 structure was essential for the LHC due to both the limited space available in the existing Large Electron-Positron collider tunnel and the cost. The second innovation was the bold move to use superfluid helium cooling on a massive scale, which was imposed by the need to achieve a high (8.3 T) magnetic field using an affordable Nb-Ti superconductor. In this article, no attempt is made to give a comprehensive review of the machine design. This can be found in the LHC Design Report [1], which gives a detailed description of the machine as it was built and comprehensive references. A more popular description of the LHC and its detectors can be found in [2]. Instead, this is a more personal account of the project from approval to commissioning, describing some of the main technologies and some of the trials and tribulations encountered in bringing this truly remarkable machine alive.

Principles for timing at spallation neutron sources based on developments at LANSCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, R. O.; Merl, R. B.; Rose, C. R.

2001-01-01

Due to AC-power-grid frequency fluctuations, the designers for accelerator-based spallation-neutron facilities have worked to optimize the conflicting demands of accelerator and neutron chopper performance. For the first time, we are able to quantitatively access the tradeoffs between these two constraints and design or upgrade a facility to optimize total system performance using powerful new simulation techniques. We have modeled timing systems that integrate chopper controllers and chopper hardware and built new systems. Thus, at LANSCE, we now operate multiple chopper systems and the accelerator as simple slaves to a single master-timing-reference generator. Based on this experience we recommend that spallationmore » neutron sources adhere to three principles. First, timing for pulsed sources should be planned starting with extraction at a fixed phase and working backwards toward the leading edge of the beam pulse. Second, accelerator triggers and storage ring extraction commands from neutron choppers offer only marginal benefits to accelerator-based spallation sources. Third, the storage-ring RF should be phase synchronized with neutron choppers to provide extraction without the one orbit timing uncertainty.« less

Space charge tune shift, fast resonance traversal, and current limits in circular accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rees, G.H.

1996-06-01

Space charge tune shifts, fast resonance traversals, and current limits are important design issues for low energy, high power circular accelerators. Areas of interest are accumulator rings and fast cycling synchrotrons, and typical applications are for pulsed spallation neutron sources, heavy ion fusion storage ring drivers, and booster injectors for high energy proton and ion facilities. Aspects of the three topics are discussed in the paper. {copyright} {ital 1996 American Institute of Physics.}

Preparation, one- and two-photon properties of carbazole derivatives containing nitrogen heterocyclic ring

NASA Astrophysics Data System (ADS)

Zhang, Yichi; Wang, Ping; Li, Liang; Chen, Zhimin; He, Chunying; Wu, Yiqun

Preparation of recording materials with high two-photon absorption activities is one of the important issues to superhigh- density two-photon absorption (TPA) three-dimensional (3D) optical data storage. In this paper, three new carbazole derivatives containing nitrogen heterocyclic ring with symmetric and asymmetric structures are prepared using ethylene as the π bridge between the carbazole unit and nitrogen heterocyclic ring, namely, 9-butyl-3-(2-(1,8- naphthyridin)vinyl)-carbazole (material 1), 9-butyl-3,6-bis(2-(1,8-naphthyl)vinyl)-carbazole (material 2) and 9-butyl-3,6- bis(2-(quinolin)vinyl)-carbazole (material 3). Their one photon properties including linear absorption spectra, fluorescence emission spectra, and fluorescence quantum yields are studied. The fluorescence excited by 120 fs pulse at 800 nm Ti: sapphire laser operating at 1 kHz repetition rate with different incident powers of 9-butyl-3-(2-(quinolin) vinyl)-carbazole (material 3) was investigated, and two-photon absorption cross-sections has been obtained. It is shown that material 3 containing quinoline rings as electron acceptor with symmetric structure exhibit high two-photon absorption activity. The result implies that material 3 (9-butyl-3-(2-(quinolin) vinyl)-carbazole) is a good candidate as a promising recording material for super-high-density two-photon absorption (TPA) three-dimensional (3D) optical data storage. The influence of chemical structure of the materials on the optical properties is discussed.

FIRST BEAM TESTS OF THE APS MBA UPGRADE ORBIT FEEDBACK CONTROLLER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sereno, N. S.; Arnold, N.; Brill, A.

The new orbit feedback system required for the APS multi-bend acromat (MBA) ring must meet challenging beam stability requirements. The AC stability requirement is to correct rms beam motion to 10 % the rms beam size at the insertion device source points from 0.01 to 1000 Hz. The vertical plane represents the biggest challenge for AC stability which is required to be 400 nm rms for a 4 micron vertical beam size. In addition long term drift over a period of 7 days is required to be 1 micron or less at insertion de- vice BPMs and 2 microns formore » arc bpms. We present test re- sults of theMBA prototype orbit feedback controller (FBC) in the APS storage ring. In this test, four insertion device BPMs were configured to send data to the FBC for process- ing into four fast corrector setpoints. The configuration of four bpms and four fast correctors creates a 4-bump and the configuration of fast correctors is similar to what will be implemented in the MBA ring. We report on performance benefits of increasing the sampling rate by a factor of 15 to 22.6 kHz over the existing APS orbit feedback system, lim- itations due to existing storage ring hardware and extrapo- lation to theMBA orbit feedback design. FBC architecture, signal flow and processing design will also be discussed.« less

Calculations of the conditions for bunch leakage in the Los Alamos proton storage ring

NASA Astrophysics Data System (ADS)

Neuffer, D.; Ohmori, C.

1994-04-01

Observations are consistent with the possibility of an "ep" instability in the Los Alamos Proton Storage Ring (PSR) with both bunched and unbunched beam. The instability requires electrons to be trapped within the beam, and calculations have shown that such trapping requires leakage of beam into the interbunch gap. Observationally, leakage of beam into the gap appears necessary for the onset of the instability. In this paper we present results of studies of the longitudinal beam dynamics at PSR parameters. The studies indicate that the combined effects of the rf buncher, longitudinal space charge, and injection mismatch are sufficient to cause the observed bunch leakage. Simulation results are presented and compared with PSR observations. Variations of PSR performance parameters are considered, and methods of improving bunch confinement are suggested and studied.

STORAGE RING CROSS SECTION MEASUREMENTS FOR ELECTRON IMPACT IONIZATION OF Fe{sup 7+}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, M.; Novotný, O.; Savin, D. W.

2015-11-01

We have measured electron impact ionization for Fe{sup 7+} from the ionization threshold up to 1200 eV. The measurements were performed using the TSR heavy ion storage ring. The ions were stored long enough prior to measurements to remove most metastables, resulting in a beam of 94% ground-level ions. Comparing with the previously recommended atomic data, we find that the Arnaud and Raymond cross section is up to about 40% larger than our measurement, with the largest discrepancies below about 400 eV. The cross section of Dere agrees to within 10%, which is about the magnitude of the experimental uncertainties.more » The remaining discrepancies between our measurement and the Dere calculations are likely due to shortcomings in the theoretical treatment of the excitation-autoionization contribution.« less

Installation of a second superconducting wiggler at SAGA-LS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneyasu, T., E-mail: kaneyasu@saga-ls.jp; Takabayashi, Y.; Iwasaki, Y.

The SAGA Light Source is a synchrotron radiation facility consisting of a 255 MeV injector linac and a 1.4 GeV storage ring with a circumference of 75.6 m. A superconducting wiggler (SCW) with a peak magnetic field of 4 T has been routinely operating for generating hard X-rays since its installation in 2010. In light of this success, it was decided to install a second SCW as a part of the beamline construction by Sumitomo Electric Industries. To achieve this, machine modifications including installation of a new magnet power supply, improvement of the magnet control system, and replacement of themore » vacuum chambers in the storage ring were carried out. Along with beamline construction, installation and commissioning of the second SCW are scheduled to take place in 2015.« less

Electron-impact excitation and recombination of molecular cations in edge fusion plasma: application to H2+and BeD+

NASA Astrophysics Data System (ADS)

Pop, Nicolina; Iacob, Felix; Mezei, Zsolt; Motapon, Ousmanou; Niyonzima, Sebastien; Schneider, Ioan

2017-10-01

Dissociative recombination, ro-vibrational excitation and dissociative excitation of molecular cations with electrons are major elementary process in the kinetics and in the energy balance of astrophysically-relevant ionized media (supernovae, interstellar molecular clouds, planetary ionospheres, early Universe), in edge fusion and in many other cold media of technological interest. For the fusion plasma edge, extensive cross sections and rate coefficients have been produced for reactions induced on HD+, H2+ and BeD+ using the Multichannel Quantum Defect Theory (MQDT). Our calculations resulted in good agreement with the CRYRING (Stockholm) and TSR (Heidelberg) magnetic storage ring results, and our approach is permanently improved in order to face the new generation of electrostatic storage rings, as CSR (Heidelberg) and DESIREE (Stockholm). Member of APS Reciprocal Society: European Physics Society.

Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

NASA Astrophysics Data System (ADS)

Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

2017-08-01

Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

Development of a bunch-by-bunch longitudinal feedback system with a wide dynamic range for the HIGS facility

NASA Astrophysics Data System (ADS)

Wu, W. Z.; Kim, Y.; Li, J. Y.; Teytelman, D.; Busch, M.; Wang, P.; Swift, G.; Park, I. S.; Ko, I. S.; Wu, Y. K.

2011-03-01

Electron beam coupled-bunch instabilities can limit and degrade the performance of storage ring based light sources. A longitudinal feedback system has been developed for the Duke storage ring to suppress multi-bunch beam instabilities which prevent stable, high-current operation of the storage ring based free-electron lasers (FELs) and an FEL driven Compton gamma source, the high intensity gamma-ray source (HIGS) at Duke University. In this work, we report the development of a state-of-the-art second generation longitudinal feedback system which employs a field programmable gate array (FPGA) based processor, and a broadband, high shunt-impedance kicker cavity. With two inputs and two outputs, the kicker cavity was designed with a resonant frequency of 937 MHz, a bandwidth of 97 MHz, and a shunt impedance of 1530 Ω. We also developed an S-matrix based technique to fully characterize the performance of the kicker cavity in the cold test. This longitudinal feedback system has been commissioned and optimized to stabilize high-current electron beams with a wide range of electron beam energies (250 MeV to 1.15 GeV) and a number of electron beam bunch modes, including the single-bunch mode and all possible symmetric bunch modes. This feedback system has become a critical instrument to ensure stable, high-flux operation of HIGS to produce nearly monochromatic, highly polarized Compton gamma-ray beams.

Analysis of coupled-bunch instabilities for the NSLS-II storage ring with a 500MHz 7-cell PETRA-III cavity

DOE PAGES

Bassi, G.; Blednykh, A.; Cheng, W.; ...

2015-12-11

We present the NSLS-II storage ring that is designed to operate with superconducting RF-cavities with the aim to store an average current of 500 mA distributed in 1080 bunches, with a gap in the uniform filling for ion clearing. At the early stage of the commissioning (phase 1), characterized by a bare lattice without damping wigglers and without Landau cavities, a normal conducting 7-cell PETRA-III RF-cavity structure has been installed with the goal to store an average current of 25 mA. In this paper we discuss our analysis of coupled-bunch instabilities driven by the Higher Order Modes (HOMs) of themore » 7-cell PETRA-III RF-cavity. As a cure of the instabilities, we apply a well-known scheme based on a proper detuning of the HOMs frequencies based upon cavity temperature change, and the use of the beneficial effect of the slow head–tail damping at positive chromaticity to increase the transverse coupled-bunch instability thresholds. In addition, we discuss measurements of coupled-bunch instabilities observed during the phase 1 commissioning of the NSLS-II storage ring. In our analysis we rely, in the longitudinal case, on the theory of coupled-bunch instability for uniform fillings, while in the transverse case we complement our studies with numerical simulations with OASIS, a novel parallel particle tracking code for self-consistent simulations of collective effects driven by short and long-range wakefields.« less

NINTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daugherty, W.

2014-08-06

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The earliest 300 °F GLT O-ring fixture failure was observed at 34 months. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 72 - 96 months, which bounds O-ring temperatures anticipated during storage in K-Area Complex (KAC). Based on expectations that the 200 ºF fixtures will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures, thus providing additional time to failure data. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 54 - 57 months. No additional O-ring failures have been observed since the last interim report was issued. Aging and periodic leak testing will continue for the remaining PCV fixtures. Additional irradiation of several fixtures is recommended to maintain a balance between thermal and radiation exposures similar to that experienced in storage, and to show the degree of consistency of radiation response between GLT and GLT-S O-rings.« less

First Experiences with CMS Data Storage on the GEMSS System at the INFN-CNAF Tier-1

NASA Astrophysics Data System (ADS)

Andreotti, D.; Bonacorsi, D.; Cavalli, A.; Pra, S. Dal; Dell'Agnello, L.; Forti, Alberto; Grandi, C.; Gregori, D.; Gioi, L. Li; Martelli, B.; Prosperini, A.; Ricci, P. P.; Ronchieri, Elisabetta; Sapunenko, V.; Sartirana, A.; Vagnoni, V.; Zappi, Riccardo

A brand new Mass Storage System solution called "Grid-Enabled Mass Storage System" (GEMSS) -based on the Storage Resource Manager (StoRM) developed by INFN, on the General Parallel File System by IBM and on the Tivoli Storage Manager by IBM -has been tested and deployed at the INFNCNAF Tier-1 Computing Centre in Italy. After a successful stress test phase, the solution is now being used in production for the data custodiality of the CMS experiment at CNAF. All data previously recorded on the CASTOR system have been transferred to GEMSS. As final validation of the GEMSS system, some of the computing tests done in the context of the WLCG "Scale Test for the Experiment Program" (STEP'09) challenge were repeated in September-October 2009 and compared with the results previously obtained with CASTOR in June 2009. In this paper, the GEMSS system basics, the stress test activity and the deployment phase -as well as the reliability and performance of the system -are overviewed. The experiences in the use of GEMSS at CNAF in preparing for the first months of data taking of the CMS experiment at the Large Hadron Collider are also presented.

Collisional disruption of gravitational aggregates in the tidal environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyodo, Ryuki; Ohtsuki, Keiji

2014-05-20

The degree of disruption in collisions in free space is determined by specific impact energy, and the mass fraction of the largest remnant is a monotonically decreasing function of impact energy. However, it has not been shown whether such a relationship is applicable to collisions under the influence of a planet's tidal force, which is important in ring dynamics and satellite accretion. Here we examine the collisional disruption of gravitational aggregates in the tidal environment by using local N-body simulations. We find that outcomes of such a collision largely depend on the impact velocity, the direction of impact, and themore » radial distance from the planet. In the case of a strong tidal field corresponding to Saturn's F ring, collisions in the azimuthal direction are much more destructive than those in the radial direction. Numerical results of collisions sensitively depend on the impact velocity, and a complete disruption of aggregates can occur even in impacts with velocity much lower than their escape velocity. In such low-velocity collisions, the deformation of colliding aggregates plays an essential role in determining collision outcomes, because the physical size of the aggregate is comparable to its Hill radius. On the other hand, the dependence of collision outcomes on impact velocity becomes similar to the case in free space when the distance from the planet is sufficiently large. Our results are consistent with Cassini observations of the F ring, which suggest ongoing creation and disruption of aggregates within the ring.« less

A drift chamber constructed of aluminized mylar tubes

NASA Astrophysics Data System (ADS)

Baringer, P.; Jung, C.; Ogren, H. O.; Rust, D. R.

1987-03-01

A thin reliable drift chamber has been constructed to be used near the interaction point of the PEP storage ring in the HRS detector. It is composed of individual drift tubes with aluminized mylar walls.

Tunable optical analog to electromagnetically induced transparency in graphene-ring resonators system

PubMed Central

Wang, Yonghua; Xue, Chenyang; Zhang, Zengxing; Zheng, Hua; Zhang, Wendong; Yan, Shubin

2016-01-01

The analogue of electromagnetically induced transparency in optical ways has shown great potential in optical delay and quantum-information technology due to its flexible design and easy implementation. The chief drawback for these devices is the bad tunability. Here we demonstrate a tunable optical transparency system formed by graphene-silicon microrings which could control the transparent window by electro-optical means. The device consists of cascaded coupled ring resonators and a graphene/graphene capacitor which integrated on one of the rings. By tuning the Fermi level of the graphene sheets, we can modulate the round-trip ring loss so that the transparency window can be dynamically tuned. The results provide a new method for the manipulation and transmission of light in highly integrated optical circuits and quantum information storage devices. PMID:27941895

Spin Transparent Siberian Snake And Spin Rotator With Solenoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koop, I. A.; Otboyev, A. V.; Shatunov, P. Yu.

2007-06-13

For intermediate energies of electrons and protons it happens that it is more convenient to construct Siberian snakes and spin rotators using solenoidal fields. Strong coupling caused by the solenoids is suppressed by a number of skew and normal quadrupole magnets. More complicate problem of the spin transparency of such devices also can be solved. This paper gives two examples: spin rotator for electron ring in the eRHIC project and Siberian snake for proton (antiproton) storage ring HESR, which cover whole machines working energy region.

The NUSTAR project at FAIR

NASA Astrophysics Data System (ADS)

Nilsson, Thomas; the NUSTAR Collaboration

2015-11-01

The FAIR facility, under construction at the GSI site in Darmstadt, will be addressing a wealth of outstanding questions within the realm of subatomic, atomic, plasma, bio-physics and applications through a combination of novel accelerators, storage rings and innovative experimental set-ups. One of the key installations is the fragment separator Super-FRS that will be able to deliver an unprecedented range of radioactive ion beams in the energy range of 0-1.5 GeV u-1. These beams will be distributed to three branches, each with its unique domain with respect to beam energies and properties. The high-energy branch will permit reactions with radioactive beams at relativistic energies, whereas the low-energy branch will supply decelerated beams for high-resolution spectroscopy, traps and laser spectroscopy. Finally, the ring branch will uniquely permit stored and cooled exotic beams for a range of methods only possible in a storage ring. Thus, by developing experimental set-ups tailored for these beams, there are several complementary possibilities to gain information on key nuclei and reaction, to further our understanding on contemporary questions within nuclear structure and nuclear astrophysics. This ambitious programme is to be exploited within the nuclear structure, astrophysics and reactions collaboration.

An Orbit And Dispersion Correction Scheme for the PEP II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Donald, M.; Shoaee, H.

2011-09-01

To achieve optimum luminosity in a storage ring it is vital to control the residual vertical dispersion. In the original PEP storage ring, a scheme to control the residual dispersion function was implemented using the ring orbit as the controlling element. The 'best' orbit not necessarily giving the lowest vertical dispersion. A similar scheme has been implemented in both the on-line control code and in the simulation code LEGO. The method involves finding the response matrices (sensitivity of orbit/dispersion at each Beam-Position-Monitor (BPM) to each orbit corrector) and solving in a least squares sense for minimum orbit, dispersion function ormore » both. The optimum solution is usually a subset of the full least squares solution. A scheme of simultaneously correcting the orbits and dispersion has been implemented in the simulation code and on-line control system for PEP-II. The scheme is based on the eigenvector decomposition method. An important ingredient of the scheme is to choose the optimum eigenvectors that minimize the orbit, dispersion and corrector strength. Simulations indicate this to be a very effective way to control the vertical residual dispersion.« less

Monitoring system for testing the radiation hardness of a KINTEX-7 FPGA

NASA Astrophysics Data System (ADS)

Cojocariu, L. N.; Placinta, V. M.; Dumitru, L.

2016-03-01

A much more efficient Ring Imaging Cherenkov sub-detector system will be rebuilt in the second long shutdown of Large Hadron Collider for the LHCb experiment. Radiation-hard electronic components together with Commercial Off-The-Shelf ones will be used in the new Cherenkov photon detection system architecture. An irradiation program was foreseen to determine the radiation tolerance for the new electronic devices, including a Field Programmable Gate Array from KINTEX-7 family of XILINX. An automated test bench for online monitoring of the XC7K70T KINTEX-7 device operation in radiation conditions was designed and implemented by the LHCb Romanian group.

A study of aging effects of barrel Time-Of-Flight system in the BESIII experiment

NASA Astrophysics Data System (ADS)

Liu, Huan-Huan; Sun, Sheng-Sen; Fang, Shuang-Shi; Wu, Zhi; Dai, Hong-Liang; Heng, Yue-Kun; Zhou, Ming; Deng, Zi-Yan; Liu, Huai-Min

2018-02-01

The Time-Of-Flight system consisting of plastic scintillation counters plays an important role for particle identification in the BESIII experiment at the BEPCII double ring e+e- collider. Degradation of the detection efficiency of the barrel TOF system has been observed since the start of physical data taking and this effect has triggered intensive and systematic studies about aging effects of the detector. The aging rates of the attenuation lengths and relative gains are obtained based on the data acquired in past several years. This study is essential for ensuring an extended operation of the barrel TOF system in optimal conditions.